LT - 2026 - 2027 _ ONLINE BATCH - CHEMISTRY - T2 [ BIRMANI SIR ] CLASS - 05

[00:02:00]Morning.

[00:02:08]Good morning everyone.

[00:02:11]Mean Hanmay Sridashra Sudishna. How are you all? All good.

[00:02:19]Exams over.

[00:02:22]So that was a basic exam based on the introduction what we have taught you in one week.

[00:02:30]Mara good morning. Good morning. Hello.

[00:02:34]Hello. Hello. Hello. Hello.

[00:02:41]One eyes I think.

[00:02:44]Ch. No problem. It will get okay in one two days. Vijaya Tanoj all good. So see what we are teaching you. You have to take it seriously and then you have to revise all the things on regular basis. Based on that if you are having some questions you can practice those questions also take and from today onwards we'll start with chemical bonding before this uh we were telling you some basic definitions of ionization energy electron gain enthalpy radius and all we have told you and uh then we will start with chemical bonding. So from here we will start like NCERTT we will complete chemical bonding in almost 11 lectures. 11 lectures means how many days? Why so many days? No 11 lectures that means 1 month will go on or what?

[00:03:42]Uh 3 3 3 4 12.

[00:03:45]So almost 22 24 days. So 24 days for chemical bonding. So I will suggest kids see those who are not knowing much they should see it nicely and those who are already knowing many things. So if you are having previous notes you can read that and at the same time you can do start doing questions more and more questions and you can study some other topics also. You can study some other topics also so that you can utilize the time we we will be having 22 to 24 days for completing this bonding chapter.

[00:04:18]I vitamin A deficiency is there. No carrot. Carrot you remember Jer tell me so it came in the neat exam also. No ch. So let's start this week up to which topic I think uh syllabus they will tell you ch I'm telling you so that uh you can also start uh Louisis dot structure fajans rule so what we have to complete I'm telling you like basic of bonding ionic bond properties latice energy fajans rule octate coordinate bond louis dot structure formal charge and limitations so these are the topics aa for previous classes those who have missed four class three four classes you have missed uh so you can watch those lectures online all the videos are available jet effective video and all those things compulsory you see it at least you will get basic of the topics okay so let's start bonding so bonding is very important wherever we see now bonding between teacher students parent students or friends everywhere bonding is important why we are having bonding to become become stable. If we don't have bonding with someone, we are moving here, there, anywhere. But when we are bonded, we are happy. We are stable.

[00:05:49]Okay. So bonding means what? Connection dipole not there.

[00:06:00]Question paper for online students.

[00:06:01]question paper maybe in the app app or any doubts you are having regarding the app and all then prasad gal to prasad g okay okay to ch see some basic basic definitions are there you should also read NCERTT everyone open NCERTT keep it near you so the first thing which we are going to see is what chemical bond what is a chemical ical bond definition is there on the first page of NCERTT only.

[00:06:37]It is the attractive force.

[00:06:40]It is the attractive force. Everyone take out NCRT. Put it near you. At the same time, you have to see NCERTT also.

[00:06:50]Okay. But yeah, at the same time you have to see NCERTT also. So first page board line. All the bold lines are important. We will try to write also.

[00:07:00]You can also write. So it is attractive force which holds which holds which holds what?

[00:07:08]Constituent particles. What are the constituent particles?

[00:07:13]Constituent particles like what? Like atoms you are having, ions you are having. So all these things will be hold together by some attractive force.

[00:07:31]in different chemical spaces in different chemical. So this definition we are writing after that we will not write because in long-term uh definition writing is not that much important because we don't have to write now board exams now to starting part we can do so chemical is pieces so that is only known as what bond so it is holding together the atom ions molecules that is only what bond attractive force which is holding together like see you are knowing ba HCl is there. So HCl how we are having one H is there one Cl is there they share electron they are bonded they are hold together by this bond this dash this dash shows what this dash shows coalent bond whenever you write dash coalent bond similarly we will say sir ions are there Na+ is there CL minus is there between charges the force is known as electrostatic ic force, colombic force. So opposite charges are there, electrostatic force of attraction is there, electrostatic force of attraction is there. And this is only known as what?

[00:08:50]Ionic bond. Ions are hold together by this bond. You can say clear.

[00:09:00]Okay. So then we are having a few representation like scientist coal scientist coal causal Louis approach around 1816 around 1816 Coal Lewis what he told he divided the atom he divided the atom into two parts what two parts by assume this is sodium Assume this is sodium. Sodium having how many electrons? But sodium having how many electrons?

[00:09:50]Sodium having how many electrons? You will say sir simple 11. Then also you have to reply because we are in a flow.

[00:09:57]So you will say sir two electron here 8 electron here and one electron is what valence electron what is valence electron electron in the outermost shell is known as what valence electron so this is a sodium atom he divided the atom into two parts what two parts one part is valence shell or valence electron one part is valence shell or balance electron.

[00:10:31]Okay. Rest everything.

[00:10:34]Rest everything. What is rest everything? Yeah. All this is known as what? Core. Core or what we call it? Kernel know 11 protons are there. This also you know.

[00:10:51]So the nucleus and all the inner orbital electrons these are core and the outermost part is what balance shell. So he divided into two parts. Now generally you know g one atom is neutral. How an atom is neutral? Because you have 11 proton here and you have 11 electrons.

[00:11:14]The answer they 11 proton 11 electrons.

[00:11:18]So the atom is neutral but this one electron you have kept side they go. Now how many electrons can you see? If I remove the valence electron then how many electrons you can see?

[00:11:35]If I remove the valence electron then how many electrons you can see? 10 electrons. And how many protons you are having?

[00:11:44]11 protons. 11 proton. 10 electron. So the net charge is what?

[00:11:52]+ one or not.

[00:11:54]So this core will be what? Positive because electron I have removed. Now so this core will be always positive. So they also call it positive core or positive kernel. They also call it positive core or positive kernel. So these are two parts. Then he said more what he said iniatic will be written.

[00:12:21]Louis postulated Louis postulated what he postulated by every atom wants to achieve eight electron in the valence shell like noble gases. Every atom every atom try to achieve how many electrons? Eight electrons in valance shell.

[00:12:50]Like like noble gas.

[00:12:54]Like noble gas to attain stability to get stable to get stable.

[00:13:08]So he said this atom can be assumed like a cube. I want eight electrons now. So he said key atoms can be assumed like a cube.

[00:13:24]All are here. So atoms can be assumed like a cube. Okay. With core with core at the center. This is core. I have told you already what is core. You can also imagine like this like your body we can divide it into two parts. One part is what? Skin that is like balance shell skin and rest everything bones muscle visceral organs all these are like core. So skin one part rest all core.

[00:14:04]Clear? So we can divide into two parts.

[00:14:07]Skin rest all core. Similarly, balance shell rest all core. So he assumed like this.

[00:14:17]The core is at the center of the cube. Center of cube. And how many corners are there in a cube?

[00:14:27]You will say sir eight. So these corners are occupied by valence electron.

[00:14:35]valence electron are at the corners.

[00:14:41]So now this diagram this diagram represents how many valence electron can you tell me or so that you will be active. Many people think sir I am knowing why I have to say things become boring at that time and slowly slowly your mind will move away from studies. So as I am saying you have to also say you are studying at your home in your room but you have to reply now you have to think like teacher is standing near me only and he's asking me okay so this is what one valence electron so which group one so you can say this is a representation of group one sodium lithium potassium they are like this mano if I make one more diagram diagram. If I make one more diagram, the answer this is the core and I'm writing here electrons.

[00:15:45]Can you tell me this is representing which group?

[00:15:49]But now this is representing which group?

[00:15:58]So like this type of representation we can give you. So you will say sir balance electron five valence electron five valence electron five is present in group 15 take now so these are simple if I will write eight valence electron that means noble gas that means what noble gas so these are all written in ncrt that's why we are telling you take louis also said key Only valence electron take part in chemical combination. Inner electron generally don't take part. Now only valence electron take part in chemical combination. Generally inner electron don't take part. Now so it is written in nrt only valence electron take part in chemical combination.

[00:16:57]When you are making bonds then who will take part? valence electron generally inner electron don't take part generally don't take part because we are knowing most of the case valence electrons are taking part in bonding inner electrons are protected well protected like these words they will use in NCRT you can read all these things okay so aatum next we will talk about tie Types of bond.

[00:17:33]Types of bond. So we can say there can be strong bond or there can be weak forces. There can be what? Weak forces. Strong bond or you can say strong forces. Okay. What is the classification of a strong bond? We say bond energy more than 42 kilojoule per mole. 42 kilojoule per mole is considered as strong bond. Now you will say sir what are the examples of a strong bond to ba? Ionic bond is there.

[00:18:11]Coalent bond is there. Then what?

[00:18:15]Coordinate bond is there.

[00:18:18]Coordinate bond is also a type of coalent bond only. You will study later.

[00:18:25]Coordinate bond is also a type of coalent bond. But we can study separately. Then fourth group bull which one I am missing. Can you tell me which bond I have not written till now?

[00:18:42]Which bond I have not written?

[00:18:46]Yo, which bond? I have not written.

[00:18:57]Yes, correct. So, I have not written metallic bond. I have not written metallic bond. Metallic bond. Okay. Then there is other name of coordinate bond.

[00:19:11]Coordinate bond is also known as dative bond. Ionic bond is also known as electrovalent bond.

[00:19:22]Correct.

[00:19:25]Metallic bond is between metal and metal.

[00:19:31]between metal metal here you can say coalent bond between non-metal generally huh between what non-metal and ionic bond is in between whom between metal and non-metal generally between metal and non-metal between metal and non-metal Clear?

[00:20:04]Okay. Then let's talk about weak forces.

[00:20:08]Weak forces we say bond energy bond energy is from 2 to 48 kilojoule per mole.

[00:20:17]2 to 42 to 42. So you can clearly see there is so much gap. Now till 42 then weak forces are there. We don't call them bond also. We don't call them bond also because they are not conventional bond.

[00:20:38]Dot dot dot you write you write like this. So these are not bonds in fact. So 2 to 42 less energy here we have what more energy.

[00:20:52]One question came in uh PYQ also key which is bond energy of CC single bond and answers were like uh answers were like like 10 kilojoule per mole 100 kiloj per mole 400 kiloj per mole 1,000 kiloj per mole.

[00:21:27]So we don't have to remember it. But what do you think approximately? What should be the answer?

[00:21:36]But approximately what should be the answer approximately carbon carbon single bond energy. We are talking about single bond.

[00:22:08]So you are going this is a coalent bond carbon carbon single bond energy is around how much but now you have studied so much hydrocarbon chapter is there in that alkan is there alken is there alkine is there alkane alken alkine this is in fact a pyq question it came around I think 2015 16 and all 156 this came around 11 2011 around 101 huh 10 kgj per mole. 10 kg per mole. You cannot say only because that is a case of weak force.

[00:22:56]So you can Google it out. No sir, how much energy is there? Carbon carbon single bond. I will also show you who can do fast. You are at home at least something to we can use now carbon carbon single bond energy single bond energy.

[00:23:15]Now this thing we cannot do in neat exam. So it will come around 33040.

[00:23:21]So we have the data 347 kiloj per mole.

[00:23:25]So my answer should be what? Fourth actual data is 347 kilojoule per mole or 83 kilo calalorie 83 kilo calalorie per mole.

[00:23:44]So when you will go in hydrocarbon chapter now you will find there single bond energy around 347 double bond energy around 600 700 they will write two bonds are there sigma and pi bond.

[00:23:55]So like this we are having okay. So you can observe these things once you can observe.

[00:24:02]So this should be more than 42 kilojoule.

[00:24:06]So around 400 it is there 347. Okay.

[00:24:10]Then you can talk sir what about weak forces sir?

[00:24:15]Weak forces we are saying these are not conventional bond. not conventional bond.

[00:24:27]Okay. Now this comprises of bender wall force.

[00:24:32]Venderol forces are there and what is there by hydrogen bonding. Hydrogen bonding you can say bond energy of hydrogen from 8 to 42 kilojoule per mole. Bandrol forces are 228 you can say.

[00:24:54]So this is very weak. See here both are weak. Vanderwal forces are also weak.

[00:25:00]Hydrogen bond is also weak. But this is weaker. Hydrogen bonding is comparatively stronger than Vanderval force. Hydrogen bonding is much stronger than Vanderwall force.

[00:25:16]Both are weak forces but hydrogen bonding is much stronger than vanderal force. In fact one case you remember HF HF case now they say like this F minus HF is there then hydrogen bonding is like coalent bond in fact and one chapter removed states of matter to there to they were giving data states of matter chapter it was written bond energy of hydrogen bond from 10 to 100 kilojoule per mole like this written in states of matter chapter states of matter now removed there bond energy of hydrogen is written this much okay to we will consider these as weak forces only very less bond energy you also know by vanderal force is what universal weak force universal weak force means what it is present everywhere Where between you and desk also vanderal force is there two person standing mandraal force is there but the force is so weak that no one cares no one cares now in vanderal force we are having again different different types so we will study sometime like we have dispersion force dispersion force we have dipole dipole force We have dipole induced dipole dipole induced dipole dispersion force between nonpolar between non-polar dipole moment between polar and this you can say one polar and one nonpolar.

[00:27:22]one polar and one nonpolar vector many things are not written in CRT also that then also I'm telling you dispersion force is also known as London force dipole dipole force is also known as quesom force dipole induced dipole is also known as dby force d I force.

[00:27:51]Okay.

[00:27:53]Now you can ask sir what do you mean by polar non-polar? They go. If you are having H2 and one more H2 or F_sub_2 are you having here delta plus minus? B are you having here in H2 molecule? Are you having here delta plus minus bolo bolo bolo conventional bond means coalent bond and all which you are drawing by bond here what I will do now you will see now I will put dot dot dot just attraction is there we don't count them as a bond also but now in h2 have you written like this delta plus minus as do you write like is delta plus delta minus in hydrogen do you write in florine delta plus delta minus FF atom connected same atom connected plus minus you write no same atom we don't write so these are the examples of nonpolar This is what nonpolar.

[00:29:12]Now one molecule second molecule between them the force is what? Dispersion force.

[00:29:22]Okay. Second example suppose you have HCL.

[00:29:27]If you are having HCL you say like this now sir chlorine more electrogative.

[00:29:34]So this is delta minus hydrogen less electro negative delta plus. So this is known as polar bond.

[00:29:47]This is known as what? Polar. One more you will take it's chbrr. You can take same also. You can take different also.

[00:29:55]So now what will happen? This is delta minus. This is delta plus. Between them the force will be what? Dipole. dipole bo all of you are able to understand next time suppose if I take one HCL and one hydrogen so they go these are non-conventional I'm not drawing a bond here I'm writing dot dot dot but now can you tell me what is the force between these two.

[00:30:36]What is the force between these two?

[00:30:41]HCl and H2 HCL and H2.

[00:30:51]HCL and H2. This is what? Dipole induced dipole.

[00:30:58]Dipole induced dipole because this is polar delta plus delta minus but this is nonpolar.

[00:31:11]This is what nonpolar between them. The force is what?

[00:31:19]Dipole induced dipole.

[00:31:24]So these things will come once again slowly slowly you will learn more like dipole moment topic is there dipole you studied in physics also sir equal and opposite charge separated by some distance is known as what dipole is known as what dipole clear to everyone they go in this if you are having any doubt then Tell in this. If you are having any doubt then tell no problem.

[00:32:19]Can we move ahead?

[00:32:27]Okay. So now see those who are feeling a bit key malo so this point a bit yeah or a bit fast you have said then by you are having a recorded video now you can play it once again speed you decrease. 25x you do slowly slowly it will go in your ears okay and these are basics also everyone knows but then also if you are having any doubt you can clearly say at this point you tell me once again okay so now we will talk to ionic bond ionic bond now yeah ionic bond so see you are knowing something something basic but then also I will tell you key this is bond between what I should write bond between cation and and what anion bond between cation and anion metal generally forms metal generally generally generally metal L forms cation and dash forms dash. Now you fill in the dash.

[00:33:50]What is this dash dash?

[00:33:54]Then you tell me complete transfer of fill in the dash dash.

[00:34:03]Complete transfer of dash takes place.

[00:34:20]Non-metal. Very good. Generally non-metal forms anion. Non-metal forms anion. Okay. Like this only we have to be involved in this.

[00:34:34]then only we will learn the things complete transfer of electron takes place okay like what you will say tell one example let's see like sodium is there sodium atomic number 11 1 s2 2 s2 2 p6 3 s1 can you tell me which is the valent shell I will ask you every minute I will ask you two three questions at least small Small questions China questions but you have to reply like this is not difficult. Which is the balance shell? Then you will say sir balance shell means outermost shell. Sir third shell is the balance shell. Third shell is the valence shell. Third shell is the valence shell. Okay. How many valence electron? You will say sir only one. But how many you require valence electron? Eight.

[00:35:39]So here I can lose one electron or I can gain seven electrons.

[00:35:47]Gaining seven electrons not possible. So I will lose one. When I will lose one electron I will become cation.

[00:35:58]Now what is a valance shell?

[00:36:02]Now valence shell changed. Valence shell is second orbit. Second orbit. And how many valence electrons you are having? 2 + 6 8 octed completed. Okay. What about Cl? Cl is having 17 1 H2 2 H2 2 P6 3 H2 3 P5.

[00:36:28]What is the valence shell? Third. How many valence electrons are there? Seven.

[00:36:36]It requires one. So that it can become octate. So I will take one electron and I will become 3 s2 3 s2 3p6 octate completed again. Now these cations and annions will attract each other. Complete transfer happened.

[00:37:04]Sodium loses one electron. Chlorine gains one electron.

[00:37:10]Cation annion between them by attractive force. That is only known as ionic bond.

[00:37:22]Okay. Then I will ask you one more question. Which of the following Which of the following has ionic bond? And your options are H2, F_sub_2, NH4, Cl all of these.

[00:37:48]Bolo, which is the correct answer?

[00:37:58]Which is the correct answer?

[00:38:01]You will say sir H2 I have seen sir we make like this. This is what coalent bond. F_sub_2 sir I make like this coalent bond. This NH4 CL is what? Ionic bond. How ionic bond? because we are having NH4 plus and Cl minus.

[00:38:26]But here we find a very interesting thing sir you have said the cations ions are formed by metal where is the metal here nitrogen non-metal hydrogen non-metal where is the metal then I will tell you key I have written generally metal generally by generally so generally metal forms. So this is exception type.

[00:38:58]You can say written in NCERT non-metal can also form cation like NH4 plus.

[00:39:15]So this is ammonium chloride. What is the name of this ammonium?

[00:39:21]This is ammonium ion. ammonium chloride.

[00:39:26]Next time I can give you example NH4 NO3. So you will say sir now I know NH4 plus cation is there and NO3 minus anion is there. So ammonium nitrate.

[00:39:44]Okay. So you have to read all these things. This is also written in NCRT.

[00:39:48]NH4 plus is cation formed by non-metal.

[00:39:53]Okay.

[00:39:55]Okay. Let's move forward. So next point is electrovalency.

[00:40:02]Next point is what? Electro valency. So electrovalency we will say like this.

[00:40:11]This is defined for ionic bond.

[00:40:15]This is defined for ionic bond.

[00:40:20]There is a similar word like coalency which is defined for coalent bond. Okay.

[00:40:29]So electrancy defined for ionic bond.

[00:40:34]This is simply the number of electrons gained or lost.

[00:40:43]Gained or lost by an atom in ionic bond.

[00:40:53]How many electrons lost or gain? Like NaCCl is there. You are knowing Na+ is there. Cl minus is there. So its electrovalency is + one. Cl electro valency is min -1. Suppose you have CL2 calcium. Can you tell me electrovalency of calcium?

[00:41:15]Electro valency of calcium + two. Very good. Because one atom is giving two electron. Can you tell me electrovalency of Clalency of Clinus?

[00:41:47]Don't say minus2. Wrong.

[00:41:50]You have to say -1 negative. In NCERT they write positive2 and here they write -1 per atom you have to tell CL -1 clear to everyone okay so you can do questions like this Al3 B then you will say surplus 3 here what minus one clear to everyone okay now we will write our next point that is factors favoring factors favoring ionic bond formation key how an ionic bond can be formed where it can be formed easily what are the factors which favor ionic bond they sometimes ask you this question also which of the following is ionic compound so there should be ions and one cation, one annion. So one metal, one non-metal.

[00:42:59]So generally S block elements generally S block elements with non-metal P block elements form ionic compound. You remember like NaCCl NaCCl Na is a S block element. Cl is a P block element between metal and non-metal. S block element generally form ionic compound.

[00:43:29]Clear to everyone? Okay. So what are the factors which are favoring ionic bond formation?

[00:43:39]Which is favoring ionic bond formation?

[00:43:51]Okay. Which is favoring ionic bond formation.

[00:43:58]Clear? Like see for ionic bond you require cation. Cation how we can make by losing electron.

[00:44:08]Losing electron requires ionization energy. That's why we have taught you ionization energy before.

[00:44:18]Low ionization energy means I can remove electron easily.

[00:44:24]Low ionization energy means I can remove electron easily. So low ionization energy of metal. Metal should have low ionization energy so that cation can be formed easily.

[00:44:45]Low ionization energy like what? You will prefer cesium or sodium.

[00:44:52]You will prefer cesium or sodium.

[00:44:59]Who can form ionic bond easily? Cesium or sodium?

[00:45:05]So you will say sir you have taught before down the group ionization energy decreases cesium has minimum in periodic table till the sixth period. Now so what cesium okay a sometimes now they also try to say ionization energy in terms of size.

[00:45:30]So we know D C minimum ionization energy but the size is what big. So you can say also like this big metal big metal generally it will form what?

[00:45:45]Cation easily. Okay. Second part. Second part you have to make now an what you have to make now anion.

[00:45:56]So anion how you will make by gaining electron. Gaining electron means what?

[00:46:02]Electron affinity.

[00:46:05]So next point I will write high electron affinity. High electron affinity.

[00:46:15]Okay. So like Cl you are knowing Cl takes electrons easily. It is having highest in the periodic table. A you can also say this in terms of electron gain enthalpy. But now I want more negative or more positive electron gain enthalpy.

[00:46:37]To gain electron I require more negative or more positive.

[00:46:45]Now everyone knows more negative electron gain enthalpy. Okay, negative means energy liberated like CL value you remember Cl value was - 349 florine value was - 328 here 349 energy liberated so its electron affinity was more clear okay so we have made cation and we have made anion we have made kion ion and we have made anion. So now you will say sir ionic compound ionic bond formed done.

[00:47:27]Now after this what will happen? They will combine and one more energy you'll have to remember high latis energy.

[00:47:39]High latice energy should be released.

[00:47:43]High latice energy should be released.

[00:47:48]Now we have a new term sir. What is this latice energy? Don't worry I will tell you high latis energy liberated.

[00:47:59]So once you see till here once you are able to understand then we will move to the next part.

[00:48:08]Say whatever we have taught you.

[00:48:13]I'm showing you all the slides.

[00:48:18]Bonding chapter we have started.

[00:48:20]Chemical bond definition is there.

[00:48:28]Causal Lewis approach. What is a core kernel and valence electron?

[00:48:38]You can take a screenshot if you want.

[00:48:45]Then like a cube. How you can think?

[00:48:49]Atom is like a cube. Core at the center.

[00:48:54]Valence electron at the corners.

[00:49:05]Then I told you about the bond.

[00:49:09]More bond energy, less bond energy, strong bond, weak bond.

[00:49:25]Then in weak bond, I told you hydrogen bonding.

[00:49:30]Hydrogen bonding is also a weak bond only, but it is stronger than Vanderval.

[00:49:39]Then I told you in bender wall there are so many types London force kom force dy force I told you what is dipole plus minus coming dipole you can assume that as polar molecule Okay.

[00:50:08]Then I gave you an example. I told you about ionic bond.

[00:50:18]Ionic bond loss of electron complete transfer.

[00:50:23]Metal non-metal generally then I told you key non-metal not compulsory.

[00:50:30]Non-metal can also form cation.

[00:50:42]Churali.

[00:50:45]Huh? You should see.

[00:50:52]Then we told you electrovalency and then we told factors favoring ionic bond formation.

[00:51:06]Okay.

[00:51:08]Okay. Now, next point. See here. So, we are saying whenever you break a bond, when a bond is broken, when a bond is broken, then energy is required.

[00:51:31]It is endothermic process.

[00:51:36]Endothermic process. Delta H value positive.

[00:51:43]But when you make a bond, it is always always you can say 99.9%.

[00:51:52]always you can say take so when a bond is formed they go I'm changing changing changing what changes I should make can you tell me when a bond is formed energy is but what I should write energy is released and this is What?

[00:52:24]Exoothermic.

[00:52:26]This is what exothermic process.

[00:52:33]Delta H value is what? Negative.

[00:52:38]Clear to everyone?

[00:52:41]Many people can think like this also.

[00:52:43]Now the online lectures going on. I will watch anytime. Huh? video is there in 2 p.m. I will see sometimes uh let's go for roaming now I will come in evening and I will see see discipline also so much required when lectures are there that time only you try to see now afternoon we will do study selfstudy evening we can do selfstudy so disciplined life also required otherwise today you are saying key I will watch in afternoon then you will start saying I will watch at night then you will start doing I will watch tomorrow it is already there now then sometimes you will say 2 3 days now I will watch on weekend directly so these habits costs a lot later on so we have to lead a disciplined life try to study live classes try to study from live classes if you are Having any doubt you can ask. We can interact here.

[00:53:53]Oh, you should keep on replying also.

[00:53:57]Yes. Yes. Yes. Let's see how many students are there. Everyone write once.

[00:54:01]Yes. Or you can give a thumbs up once.

[00:54:04]Thumbs up button like button.

[00:54:08]Whoever are there you are sleeping only. Uhhuh.

[00:54:16]because same names are repeating in the comment section. Huh? So that's why I want to see the others are just switch on the laptop, phone and gone.

[00:54:26]Uh uh now few names started appearing but these names are again still old only.

[00:54:40]Some people are still lazy. Uh lazy lazy ch. So when you will make a bond energy is liberated and when you break a bond energy is required. Clear? Okay. Now let's come to this point. Key factors favoring means uh factors favoring ionic bond s ionization energy I have understood. Low ionization energy means electron will be removed easily. Okay.

[00:55:09]High electron affinity means electron can be gained easily. Sir what is this latice energy? Can you tell me please to so I'm talking about the next topic that is what latis energy latis energy latis energy is represented by u generally we don't write u simply we will write l e l e but official representation is like u take a latis energy so first of all see you will have to understand what is a latis is see there was a chapter called solid state very important chapter very imagination based chapter a bit difficult also because people cannot imagine everything now but that chapter is now removed in that chapter we used to tell what is solid what are the different structures they will say romic monocinic romboed cubic hexagonal so many words were there you simply think like this any solid is made up of a repeating unit. Now like you have a Rubik's cube. You think like this Rubik's cube is there one small cube there that is known as unit cell.

[00:56:26]That is known as what? Unit cell. This small cube repeats in every direction to make that Rubik's cube. That Rubik's cube is known as what? Crystal latice.

[00:56:40]That is small but you can think in case of atom it is invisible in fact now with naked eye that means what so many unit cell will combine so many so many unit cell will combine in all the direction then you will get what latice like one building is there building is made up of what rooms so you can imagine one room is like one unit cell one room is like one unit cell. Now this one room repeating in all the direction up, down, left, right, you get a full building.

[00:57:19]This full building is known as what?

[00:57:21]Latis, crystal latice. Okay. So latice energy is the energy required or you can say in terms of release also when you will make this building latice energy will be liberated.

[00:57:36]Okay.

[00:57:38]What is latis energy? So you can write the definition in terms of released also absorbed also. So I can say it is the energy required.

[00:57:50]It is the energy required to break to break what? To break one mole. Generally all the energy definitions are with respect to one mole. It is the energy required energy. It is the energy required to break one mole of solid ionic compound. 1 mole of solid ionic compound into gaseous ions into gasous ions.

[00:58:32]Malo na solid is there. You break this into Na+ gas and Cl minus gas.

[00:58:42]Now you have to take how many moles they go? Solid ionic compound. You have to take one mole. Means here one written one mole. Gaseous compulsory. If you'll write here aquas wrong gaseous ions if you write atom slowly see how they will trap you. They will write everything.

[00:59:05]Last May here they will write atom gone wrong.

[00:59:11]Tata. Bye-bye.

[00:59:15]Gaseous ions.

[00:59:23]Huh? You can say big structure which is visible to eye. No because atoms you are not able to see now repeating it is a 3D you can say it is a 3D network or repetition of unit cell in all the direction okay why you don't have to write their gaseous atom ions ions should be there okay now in this you can say whatever energy here required in this reaction this is equals to latis energy of NaCCl and that is Got 70 788 788 kilojoule per mole. This is 788 kilojoule per mole.

[01:00:07]Clear? Up. They can tell reverse also you can say sir breaking then to energy required then if I will make it if I will make ncl then energy will be what? liberated.

[01:00:26]Correct? I can write the definition in terms of liberation also. Key it is the energy released or you can simply say like this.

[01:00:38]It is the energy released. Can you tell me what I should write so that you will think key everything to similar similar only I will copy everything once they go where I will make changes you see carefully where I will make changes and if I miss something then you tell me they go where I'm making changes everyone seen the o see on the board so I am writing now it is the energy required n I'm writing what energy released to break n to make or you can say to form what you have to form again you have to form one mole of solid ionic compound from gaseous ions from what gasous ions. So exactly reverse I have done. Before this I was breaking one mole of solid ionic compound. Now I am making one mole of solid ionic compound. Okay.

[01:01:53]Then what? Then see what I'm doing. I'm removing this. I'm removing this either.

[01:02:04]And you can see clearly I have made one mole of solid ionic compound here. One a this is also known as a latice energy or see here you are making now here you are what making compound. So they also write latis energy of formation to have more clarity. They write latis energy of formation.

[01:02:32]They will say latis energy of formation.

[01:02:35]Can you tell me its value?

[01:02:39]But now can you tell me its value? Latis energy of formation. When you are making the latis that can be also known as latis energy of formation. This word is used in NCERTT. That's why I'm telling you. So you can say - 788 - 788 Lis energy of formation clear to everyone.

[01:03:12]Latis energy of formation. Very good.

[01:03:14]Very good. Many students are writing.

[01:03:15]Very good. I appreciate your efforts.

[01:03:18]Okay. You should be active. Clear? So see the conversion. This is important one mole of solid ionic compound converted to gaseous ions or you have to make it. So malo suppose when you are making this lattice so much energy is liberated that means that compound will be what? Stable. That compound will be what? Stable. So they say like this latice energy.

[01:03:47]Latis energy is a qualitative measure of qualitative measure of stability of a compound.

[01:04:03]Stability of a compound means by latis energy we can tell about stability of a compound. You can say more latice energy that implies more stable ionic compound.

[01:04:22]Generally latice energy is defined for ionic compounds only. So more stable ionic compound.

[01:04:33]Now you can say sir that means the latice energy part very important. So I should compare whose latice energy more and whose latice energy is less.

[01:04:47]But the question is now how you will compare are you knowing the formula?

[01:04:54]How you will compare? So don't worry I will tell you by they go you know this thing key one charge Q1 is there one charge Q2 is there separated by some distance there will be electrostatic force between them that is K q1 Q2 by R² you are knowing this or not electrostatic force or kumbic force kulum's law they say very good K1 Q2 by R² so this is force this This is what force manu if I write only k q1 q2 by r k q1 q2 by r then what is this bad though?

[01:05:39]If I write k q1 q2 by r then what is this?

[01:05:56]Kabra this is what energy potential energy we are saying. So with this we can tell Q1 Q2 two charges separated by some distance. I can say latis energy is directly proportional to product of charges.

[01:06:17]Latis energy directly proportional to product of charges. and inversely proportional to size.

[01:06:26]Product of charges and inversely proportional to size. They go latice energy directly proportional to product of charges.

[01:06:58]and inversely proportional to what size done.

[01:07:06]Charge first priority. First we will check charge.

[01:07:10]First we will check what? Charge.

[01:07:15]Okay.

[01:07:17]So let's do it. How to check charge and all? Let's do some questions. Like suppose I'm writing L, N, K, RB, CS.

[01:07:32]You have to arrange on the basis of latis energy.

[01:07:36]You have to arrange on the basis of latis energy.

[01:07:42]Okay. So see how to do the question. You know key sir we are having one cation here and we are having one annion. You will see key annion part same. Generally what will happen? One of the ion will be same. Anion is what? Same.

[01:07:59]So we have to focus mainly on cation. We have to focus mainly on cation. Now listen carefully what we have said the latice energy directly proportional to product of charge. So first you multiply the charges 1 into 1 lithium + one chlorine minus1 just multiply the charges sign we don't require because every time kion is what net will be minus only so first priority I have said first you have to do what charge then you will find charge product to same then you will focus on size but size inversely proportional. See carefully annion part same. So focus on the size of cation.

[01:08:52]Focus on the size of cation.

[01:08:56]Ch focus on the size of cation.

[01:09:03]So now when you'll focus on the size of cation who is smallest cation can you tell who is smallest cation. So you will say sir down the group size increases that's why we told you four lectures basic basic things radius ionization energy because we require these things now radius we require here ionization energy we have written before only so that means what small size that means latice energy is what more a small size. So latice energy is what?

[01:09:44]More. Let's see second question. NF, NAC, N A B R, N A I.

[01:09:52]Again you will multiply the charges.

[01:09:53]When you will multiply the charges charge priority you will find the charges are same.

[01:10:00]This time you will find the cation part is same. Cation part is same. So I will focus on annion. Anion F minus, Cl minus, Br minus, I minus.

[01:10:17]Who is the smallest annion?

[01:10:24]Who is the smallest annion? Naf. Small size means latice energy is what? More.

[01:10:33]Like this we have to do. You can also say like this key sir can we say given charge is same now down the group size increases that means latice energy decreases. Can we say like this?

[01:10:51]When charges are same then generally in a group charge will be same only like group one you will have + one group two + two. So generally charge part will be same only. You can also write directly key as we move down the group. As we move down the group, as we move down the group, size increases, that implies latice energy decreases. This also I can say okay let's do the next question. So N A2 Mg Al2O3 A L N Can you tell about the lattice energy?

[01:11:54]Now can you tell about the latice energy?

[01:12:05]Now so first again I will multiply charges + 1 -2 1 into 2 2 into 2 3 into 2 3 into 3 nitride nitride is N3 minus oxide is 2 minus hogen is X minus Huh? So based on charge based on charge it increases. Read the question carefully. They are asking about decreasing order or they are asking about increasing order.

[01:12:48]Clearun done clear.

[01:13:00]Okay. So like this you can solve many questions like this we can solve many questions like suppose I'm talking about magnesium oxide and magnesium nitride so you can say s 2 into 2 2 into 3 clear to everyone you can compare uh like this you can compare other things also. So directly proportional to product of charges and inversely proportional to size. directly proportional to product of charges and inversely proportional to size. This is about what? Latis energy.

[01:13:48]This is about latis energy.

[01:13:53]Clear? Okay. Now let's see one special case of NaCCl.

[01:14:00]Why latice energy is so much important?

[01:14:02]We are writing formula. We are calculating it. Why this is so much important? Now last 5 10 minutes left.

[01:14:09]Don't think 5 10 minutes not important.

[01:14:12]Most important thing we are going to tell now only listen carefully.

[01:14:17]So I'm talking about formation of NaCCl.

[01:14:22]I'm talking about what? Formation of NaCCl.

[01:14:27]NaCCl structure is also known as rock salt type.

[01:14:34]This was from that chapter only solid state. This was from that chapter only solid state.

[01:14:43]Now rock salt type structure they are saying cube will be there. Na+ will be there. Cl minus will be there and so on.

[01:14:51]like this they will say take. So what they are doing now you think how NaCCl can be formed. Suppose we start the reaction with Na gas. The answer suppose we start the reaction with Na gas. Then first of all I should make a cation.

[01:15:14]Then I should make an annion.

[01:15:18]Then cation and anion will combine to form crystal latice.

[01:15:32]Okay.

[01:15:34]First I will make a cation then I will make an annion and cation and anion will combine. ionic bond formed then they will form the crystal correct okay so how I will make a cation can you tell me how I will make a kion you are knowing sir for making cation I require ionization energy Na plus gas that's why we have told you the definition of ionization energy ionization energy definition is it The energy required to remove an electron from isolated gaseous atom. Balance shell of so many things are there but gaseous atom compulsory. So I have taken gaseous atom anion. Okay. So here ionization energy of sodium that is around 495 kilojoule per mole. This much energy will be required.

[01:16:38]this much energy will be required to make this cation. Then suppose I'm having Cl gas.

[01:16:47]Class I will have to make an ion. Then electron gain enthalpy involved.

[01:16:55]Then you know we have puted these values. This is a standard question. So we should know some values. K electron gain enthalpy of CL is - 349 kilojoule per mole.

[01:17:10]So some energy is absorbed and some energy is liberated when we are trying our target is to make NaCCl crystal. How to make? I am having Na gas CL gas. I will remove one electron ion energy required here. Cl electron gain enthalpy released.

[01:17:33]Now if I ask you sum of ionization energy and electron gain enthalpy this will be approximately 146 kiloj per mole coming or not but this is approximately coming 146 kilojoule per mole.

[01:17:54]So till now overall energy is absorbed.

[01:18:02]Till now overall 146 kilojoule per mole of energy is absorbed because energy required is around 500 and released energy is around 350. So my 150 to gone by. Suppose you want to start a business that business tea stall only tea coffee selling uh investment require 500 but return you are getting only 350 rupees that means you are in a loss of 150 or not by you are in a loss of 150 or Not a manu if you are in a loss of 150 then will you do that business?

[01:19:04]Will you do that business?

[01:19:07]But if you are in a loss of 150 then will you do that business?

[01:19:14]You will say no sir. So same thing happens in chemistry also. If the net energy is absorbed then that process is not favorable.

[01:19:25]And if the net energy is released then the process is what? Favorable.

[01:19:32]So they will ask you.

[01:19:35]So they will ask you what they will ask.

[01:19:39]They will ask you by sum of ionization energy and electron gain enthalpy is positive energy absorbed.

[01:19:51]This process not physible not favorable.

[01:19:55]Then how NaCCl is formed?

[01:19:59]and how NaCCl is formed.

[01:20:04]Mau our Russian language is very good. Okay.

[01:20:09]How? So let's focus here. So what we were saying the ionization energy and electron and enthalpy net value is what?

[01:20:17]Absorbed.

[01:20:20]Okay. So the process is not favorable.

[01:20:24]Then you can say then how nl formed? Ncl by common common salt we put in papu then we eat it.

[01:20:34]How n formed?

[01:20:38]But how? How na formed? Then you will HAVE TO SAY SIR TILL NOW I HAVE not formed nacl only. I have formed only na plus and cl minus. Now I am going to solve. Now I'm going to form NaCCl. How?

[01:20:56]Then this Na+ and Cl minus will combine to form NaC solid.

[01:21:08]Na solid.

[01:21:11]This Na+ and Cl minus will combine to form NaCCl solid. Can you guess the enthalpy liberated in this case?

[01:21:22]Mad can you guess the enthalpy liberated in this case?

[01:21:32]Mau what value should come here?

[01:21:39]You will say sir this is the equation looking familiar familiar I have seen this before this is nothing else but enthalpy latis enthalpy of formation and this value will be - 788 kilojoule per mole so what you observe till here to I was in loss but when na plus and Cl minus will combine then energy will be liberated 788.

[01:22:18]So my loss is totally recovered.

[01:22:21]146 loss is totally recovered and in fact now to ba I am in profit.

[01:22:31]Now to I am in profit around 640 profit I am having. So that's why NaCCl is formed. So NaCCl is formed because large amount of latis energy is liberated which more than compensates for the loss. Like I told you now suppose we are doing business tea coffee we were in a loss of 200 rupees 500 invested we got back only 300 200 LOSS BUT THEN also remember 200 loss but then also I'm doing that business. Why?

[01:23:12]Because by side I was selling baji also masur bh baji punugunu this cell was also doing there I GOT A PROFIT OF thousand there I got a profit of 1,000 tea coffee 200 loss but budgy business 1,000 profit so that budgy business is compensating for my loss and it is not only compens compensating it is more than compensation net profit I'm having 800 net profit I am having 800 understood the point so HERE YOU WILL WRITE ONE POINT kil latattis energy liberated more than compensates and these all are lines of NCERTT more than compensates ates for the sum of ionization energy and electron gain enthalpy.

[01:24:21]My net delta H net will be 395.

[01:24:27]You can say net will be ionization energy plus electron gain enthalpy plus latis energy. And this value you are knowing this value is ba 395 approximately this is - 349 495 and this one is -788 and net value will come negative.

[01:24:54]So net energy released net energy released clear net energy released.

[01:25:09]So if I ask you why Ncl is formed due to ionization energy, electron gain enthalpy or latice energy what you will say but if I ask you we'll keep till here only if I ask you why NaCCl is formed what you will say due to ionization energy due to large electron gain enthalpy liberated or due to latis energy liberated due to High latice energy due to high latis energy. Latis energy not only compensates more than compensates latis energy more than compensates for the sum of ionization energy and electron gain enthalpy. Okay, all of you understood I think that's why this is formed. So next class again we will tell you what to do.

[01:26:03]What is the sum of ionization energy and electron gain enthalpy? Positive or negative?

[01:26:09]Sum of Sum of latice energy and electron gain enthalpy positive or negative positive but overall negative now with latis energy it is negative. So that's why some lines will be written in NCERTT. uh we will start from there in the next class. I have told you how to compare latice energy. So you can do at least let energy questions you can do whatever material you are having where they will ask directly whose latice energy is more whose latice energy is less those questions you can do. Okay. So hope you have understood enough for today. Thank you everyone.

[01:27:00]Done. Done.

[01:27:04]Okay, thanks everyone. So, but you have to study nicely and solve questions. solve some questions and you are at home any question if you are trapped you can check online solutions also but if you're not able to do then you can ask in the next classes okay you can message me then we will see it okay so thanks everyone bye-bye