In under 15 minutes, this video takes you from knowing what an electron is to writing the full electron configuration of any element in the first three periods of the periodic table. You'll see how the 2,8,8 rule connects to the structure of the periodic table, why elements in the same group have similar chemistry, and why the Bohr model is still the starting point for understanding bonding despite its known limitations.

What You Will Learn

00:46What the Bohr model of the atom shows and why it replaced earlier atomic models.

02:57How electrons are arranged in shells and what each shell represents in terms of energy.

03:43How to apply the 2,8,8 rule to fill electron shells in the correct order.

05:16How to write and interpret electron configuration notation for the first 20 elements.

06:10How the number of periods and groups in the periodic table directly reflects the shell structure of atoms.

07:58How to use group number to determine the number of outer electrons for any main group element.

10:04How to use atomic number to write the electron configuration of any element up to calcium.

13:12How the history of atomic models — from Bohr through Rutherford to Schrödinger — explains why scientists update their models.

14:19Why the Bohr model is still taught and used despite being superseded by quantum mechanics.