TGT EXAM-2026 | CHEMISTRY | PRACTICE CLASS | BY UTKARSH SIR

[00:00:00]I, Utkarsh Tiwari, your Chemistry Faculty, welcome to the online platform.

[00:00:03]We were practicing questions.

[00:00:05]Let's continue the question further.

[00:00:09]Question number 101 was which of the following sets of quantum numbers is not acceptable? Which of the following sets of quantum numbers are not acceptable? n = 1, l = 0, m = 0 ok?

[00:00:24]This is for 1s. So this value of s will be zero. It will be zero. This will be half. Ok?

[00:00:30]is 1s1. Correct? Correct. Similarly, if the value of n is one then it will be like this.

[00:00:36]The value of l cannot be one because p does not exist. This is wrong. There is no p. There is no such thing as 1 p. There is no such thing as 1 p.

[00:00:46]So the other one went wrong. The next question before us is which of the following sets of numbers is possible? Ok? Which one is possible?

[00:01:00]Which of the following sets is possible? Which of the following set of quantum numbers is possible? The set of quantum numbers is possible.

[00:01:08]Ok? How it is? Remember this. The value of s cannot be zero. So the first one went wrong. n = 4, l = 4 cannot happen. This is also wrong. n = 4, n = 4 This also cannot happen. n = 4, l = 3 so that means it can happen.

[00:01:28]4f So [sound of clearing throat] 4f in 4f this could happen. Ok? + 1 is given, then suppose one is n lx then the value of n is 4. The value of l is three. What is the value of m?

[00:01:47]The value of m is -3, right? The value of a l the value of m the value of n is four. The value of m is three.

[00:01:55]Why? because f is in. f has three.

[00:01:59]And the value of s will depend on where the value of m is. Three is a given.

[00:02:04]So what are the conditions in this given?

[00:02:07]So look, n = 4, l = 3, m = -2, so this is three.

[00:02:11]So how did it go?

[00:02:14]- 3 -2 -1 0 +1 +2 +3 ok? So that means if it has -2 in it then -2 is correct. S is up clockwise. This is also correct.

[00:02:28]So its correct option will be D.

[00:02:31]What will be its correct option? Yes.

[00:02:32]All the couples are doing it right. That means I am telling this only for 4F. Ok? It is not necessary that there should be a forest. This is not necessary.

[00:02:41]Next, it is said in Bohr's atomic model that when an electron jumps from n1 to n3, how much energy is absorbed or emitted, how much is emitted or absorbed, okay, so see what we put, we solved it by keeping e equal to 2.18 * 10 ^ - 111 z² / n² square.

[00:03:12]Jumping from first to third.

[00:03:15]Ok? So as it goes up, the energy increases and it will absorb it. First of all understand what will he do? If it goes up it will absorb it.

[00:03:24]So let's keep e equal to delta e equal to 2.18 * 10 to the power of -1, okay? 1 - 1 to the power of n because how did the n value become? If it is 3 then what will happen? 2.18 * 10 to the power -1 becomes 9 * 8 / 9. We will solve this. When we solve this, the value we get is B, that is, 091 10 to the power -10 arg. So its correct option will be B.

[00:04:04]Next question what is the series limit for Balmer series of H spectra? The Series of the Limit of the Balmer Series of the H Specter. So see, for this we are writing it to you separately. You guys remember this.

[00:04:19]Ok? This is written separately.

[00:04:22]See which one remains?

[00:04:28]Lyman Series.

[00:04:32]Ok?

[00:04:34]Balmer series, Pash series, Bracket series, P full series or Humphery, how was Tarangad, this 3646 to 6565, Strong this 824 to 18751, Angstro this 14580 to 18751, Angstrong this 22750 to 40 40512 Angstro this 32810 to 38788, we have given these ranges to you in writing.

[00:06:21]We have written this range for you. Lyman's wavelength ranges from 912 to 912, how much does it range from 1260, Balam series ranges from 3646 to 6565, Paschen's range ranges from 8204 to 87, 18751 bracket ranges from 147518 to 18751, P Food's range from 22750 to 40512, Humphery's range from 32810 to 38800788, so what were you asking us in the question? He was asking us whose?

[00:07:01]Of the Balam series. So where did the Ballmer series go? See how much remains? It remains 3646.

[00:07:06]How are you [nasal sound]? 3646. So what is its correct option? It remains 3646.

[00:07:12]Ok?

[00:07:15]Please note down what we have given you earlier.

[00:07:18]Next, where does the hydrogen atom need the most energy to transition to nuclei?

[00:07:26]These are as many as n are given. The has been written. Ok? n How is this? n remains.

[00:07:35]How is this? n remains. Which of the following electron transitions in a hydrogen atom would require the greatest amount of energy? Which contains the greatest amount of energy. Ok? So look, remember, we always go from first to second. Remember that the previous one remains this remains 13.6 electron volts. The second one is minus 3.4, what is the difference? of 10.2 electron volts. It is 10.2 electron volts. So that means it's A 10.2 electron volts. Next, which of the following atoms is isoelectronic? But the neon atom has the same electron pair.

[00:08:25]Ok? See how many live in it? It has 12 electrons, it has 10 electrons, atomic number nine. There will be no oxygen atom. The oxygen atom has eight.

[00:08:39]Eight live near nitrogen.

[00:08:43]How many did he have? Eight electrons. So who has 10 electrons? What is this equal to? This is equivalent to neon. How it is?

[00:08:52]Equivalent to neon.

[00:08:54]Next is done. The number of electrons in a molecule of CO2 is The number of electrons in a molecule of CO2 22 44 66 88. Look at CO2, how much carbon we have.

[00:09:11]How does 8 * 2 look in oxygen? How did 6 + 16 become?

[00:09:18]How are you 22, brother? It's 22 now. Ok? So 107 [laughter] became the correct option. It's 22 now. The next question is what is the maximum number of valence electrons any p orbital can accommodate. Any p orbital can accommodate a maximum of four electrons or six electrons.

[00:09:36]Two electrons with parallel spins Two electrons with opposite spins.

[00:09:38]So look, there are two electrons in s.

[00:09:41]How many live in P? Six electrons. D contains 10 electrons. F has 14 electrons. So how many are there? How many are there in P?

[00:09:57]How many is six electrons? Six electrons. The valence electrons of rubidium have the correct set of all four quantum numbers.

[00:10:09]The correct set of the four quantum numbers for the valence electrons of rubidium Z37. The atomic number of rubidium is 37.

[00:10:21]What happened? Krypton is 36 and how will it be after this, see how we remember lithium 1s sodium 2s potassium 3s okay lithium sodium potassium rubidium so how will it be 4s so that means how will it be here?

[00:10:55]What will 4s1 be like? 4s1 Lithium, sodium, potassium, rubidium. Ok? So it has been asked in Rubidium that will there be any value in Rubidium? Ok?

[00:11:10]So what will happen to rubidium? Something has gone a little wrong. Please take care.

[00:11:21]Hydrogen comes first. There is a forest of hydrogen. In this it remains first 1s1 last. Ok? Please correct this a little. How about hydrogen? Atomic number one 1s1 of lithium remains three. The one inside was helium 2s1, then after that was 11, then what was sodium in it, how was neon 3s1, then 19 potassium krypton 4s1, then 37 rubedium KR, what was there here? AR is it okay? How was it? 5s1 5s1 So that means how did it go? Remember, we will take it out for 5s1. For 5s1 it remains nlx. The value of n is 5, the value of l is 0, the value of m is 0, the value of s is plus 1/2.

[00:12:41]Ok? The value of n is five, the value of l is zero, the value of m is zero, the value of s is half. So, how did it happen?

[00:12:48]Look here the value of n has become five.

[00:12:51]Ok? The value of l becomes zero, m becomes zero. Ok? So, in what ways did this happen? There should be five here as per rules. Then this was option D.

[00:13:02]How was it? There used to be a D option. Six is written which is wrong.

[00:13:08]What is the radius of the nucleus of an atom? 10 to the power of -10 centimeters 10 to the power of -13 centimeters 10 to the power of -15 or 10 to the power of -8 the radius of an atomic nucleus is what is the order 10 to the power of -10 centimeters 10 to the power of -13 centimeters 10 to the power of -15 centimeters 10 to the power of -8 centimeters so how does this happen okay this happens 10 to the power of -3 centimeters okay what was the energy of one photon in 2000 angstrom ray what is the ratio of the energy of one photon to the energy of four 2000 we have to find out how E is equal to we have E1 equal to HC/λ1 second how will E2 be equal to HC/λ2 if we divide it then how will it be λ2 cancels out λ2 /λ1 that means it will become 4000 / 2000 It will be cancelled. If 2 * 2 = 4 then how will 2 become 1? 2 Anu will become one. How much will it be? 2 1 means it will be D option.

[00:14:24]Next question. The orbital diagram on which the principle of scarcity is violated. Two on 2s two on 2px one is correct.

[00:14:37]One on this and then two on this, how is this possible? This is correct. This is correct. This is correct. This is wrong.

[00:14:44]How did this happen, first one and then two?

[00:14:46]First one, then two. In what way would this be wrong? Next it is given that the angular momentum of the orbital of electrons in the 2s orbital is the orbital angular momentum of an electron in the 2s orbital okay what remains for 2s what remains for nl so μ is equal to l + 1h/ 2π okay what is this value is 0 the value of l is zero for whom? For s. So what did we keep here? So how did it become 0 0 + 1/2π? It became zero.

[00:15:31]How are you? Became zero. B of 113.

[00:15:35]Ok? px Specifies the number of nodal planes. Will the number of nodal planes in a px be one, two, three, or zero?

[00:15:45]What will happen? This has been asked. 1 2 3 or zero, so see, the value of l is one for p, whether it is px or py or pz, then its correct option will be a.

[00:16:01]Next, what will be the number of radial nodes of 3s 2p orbital? The number of radial nodes of 3s and 2p radial nodes is asking.

[00:16:12]So for 3s we will calculate n - l - 1 3 - 0 - 1 i.e. 2 and similarly for 2p we said n - l - 1, okay? How will it be? How will 2-1-1 happen? 0 then how much will it be? 2 and 0 came. How many came? 2 and 0 okay? So this is it.

[00:16:41]What will the correct option be like? A. In the next iso electronic, Cl- is affected by AR- and Ca2.

[00:16:50]What affects size? Effective nuclear charge. Ok? Look, how many protons are there in Ca2+? Has 20 protons. Ok?

[00:17:05]In +2. But there are 18 electrons. Same way in AR, right? How many are in AR? Has 18 protons. There are also 18 electrons here. And Cl- has 18 electrons but 17 protons. So how will it be?

[00:17:28]What will happen to us when we go from left to right? If we go from left to right, then how will it be if we go from left to right, how will it be if we come from right to left, will the effective nuclear charge increase, will the effective nuclear charge become, how will the effective nucleus charge become, okay, so that means its correct option is done son, how will it become for B 116, B Next, among the following, the energy of 2S orbit is the lowest. Of potassium, sodium, lithium or hydrogen? Which one has the least? It has been asked which one has the least? Ok?

[00:18:31]Decreases with increasing size.

[00:18:33]So which one has the biggest size? Of potassium.

[00:18:37]So this one will have the lowest.

[00:18:40]Whose size became the biggest? of potassium. So who will have the least? It will be of potassium only. Ok? Next question is. It is said that in lithium, what will the second Bohr orbit become in the context of A note? Who have you told us about? About Bohr. How does R remain equal?

[00:19:02]R0 N²/Z ok? N spoken in second grade R not. Ok? For the second class, we have been asked to do the square of two. Ok?

[00:19:17]What do we care? What would be the value of the second Mor orbital in terms of a note of 2 plus lithium? Ok?

[00:19:28]What will be the radius of the second Mor orbit with respect to the a note he was given?

[00:19:30]This was asked of us. Ok? So what will we put in it? r = n will put a dot.

[00:19:37]Ok? It has been asked for lithium, if the atomic number is three then it will become four 4r0/ 3, here r not up has been considered as a, okay so a not up will become 3, then its correct option will be d, its correct option will be d for 118, next question is electromagnetic spectrum, that region where Barma series occurs. Ok? So the Balmer series is visible, meaning it remains in the visible. In which does he live?

[00:20:10]Lives in Visible.

[00:20:13]Ok? Next is done. Now it says in the statement given below Bohr's theory in Given Bills is responsible for the stability and line spectrum of this ion. Ok? As with hydrogen, Bohr's theory was unable to explain the splitting of the spectral lines in the presence of a magnetic field. Based on the above statements, which statement is most correct? Ok?

[00:20:37]Both statements one and two are true. Statement one is false, two are true. Ok? That's what he's saying right.

[00:20:43]Statement one is correct, one is wrong, the other is correct. One statement is wrong, how is the other? Correct.

[00:20:50]Next question is given that both the statements given below are given below.

[00:20:56]Rutherford's gold foil experiment does not explain the line spectrum of the hydrogen atom. Ok? The second given Bohr model of the hydrogen atom contradicts the Nisch theory of the Hahn class.

[00:21:08]Ok? Both of these are given.

[00:21:11]It also asks which one is wrong?

[00:21:13]Which one is correct? Ok? So Rutherford was not able to do this and the hydrogen spectrum was misinterpreted by Huygens Dam. Both of these are correct. So how is the statement? Statement one is false but statement two is true. Statement one is true but statement two is false. Both statements one and two are false. Then given statement one and statement two both are true. So this is the correct option. This is done son D. Both are correct.

[00:21:41]Consider the following electron pairs.

[00:21:43]A B C D is given.

[00:21:46]Which is the most correct pair among A B C? We have to see this and tell. Which of these is the most accurate? Ok? So remember in this that the one with b is the most correct. Take it out and see. n = 3.

[00:22:01]This is d. Ok? So this value comes out correct in this.

[00:22:04]Here also it is being told that 3D has been provided.

[00:22:07]So this is correct. So its option B is correct. That means this is B of 22. Next Quant Which of the following sets is not acceptable? Which set is not accepted? Look, n equals this could be 3d. This can also be 3D. How can this be? Three means 3f, so there is no such thing as 3f.

[00:22:29]So that means this is not acceptable.

[00:22:32]Ok? It is not acceptable that it does not remain like this. Ok? Next. It is said that in the two statements given below, one statement is labelled as Assertion A and the other as Assertion R. The 2s orbital of the hydrogen atom has a higher energy than the two x orbitals of lithium.

[00:22:52]Energy order in similar shells increases with increase in atomic number. So in this also we have to tell people which is right and which is wrong. So the first one is saying that the energy of the th orbit of this hydrogen atom is more than the energy of lithium.

[00:23:05]He is saying the right thing. Ok?

[00:23:08]With increase in atomic number, the number of valence electrons in subshells decreases. There are less.

[00:23:13]This is wrong. So the assertion is true but the reason is false. So its correct option will be C. Assertion is true but reason is false.

[00:23:31]What are the values ​​of nm i.e. m quantum numbers for azimuthal quantum number l that remain invariant? Ok? So where do we get the value of m from?

[00:23:37]From 12+1. This is a relationship. So out of these, this two is written wrong. Otherwise it remains true that m = 12 + 1. Right kids? So this was the last question for today. We will come forward in the next class i.e. tomorrow with many more questions and will practice. I think you would have found these questions correct. So please look at this and understand it. We will meet tomorrow. Till then Jai Siyaram.