Bohr Models Explained in 60s

Added: 2026-05-17

[00:00:00]Bohr models are representations of atoms that approximate the number and location of an atom's electrons. The nucleus is in the center and then electrons are organized into energy levels. The first energy level can hold two electrons and then the rest can hold up to eight. And you can read a Bohr model as a way to identify an atom. For example, if you see two electrons in the first level and six in the second, that atom has eight total electrons. And the atomic number eight on the periodic table is oxygen.

[00:00:26]If you see a Bohr model like this with two, eight, and then one valence electron, that's 11 total electrons and so that atom is sodium. And there's a shortcut here. For main group elements, the number of valence electrons matches the group number on the periodic table.

[00:00:40]So group one elements all have one valence electron, group two have two, and so on. So if you know the number of valence electrons, you can at least narrow down where the element is on the periodic table really fast. And the number of valence electrons explains how those atoms will react. And so if two atoms have the same number of valence electrons, they're going to react in similar ways.