Electronic Structure

Question 1

Electron Shell Rules:

Answer 1

Electrons always occupy shells (sometimes called energy levels)

The lowest energy levels are always filled first - these are the ones closest to the nucleus.

Only a certain number of electrons are allowed in each shell 1st shell: 2 2nd shell: 8 3rd shell: 8

Atoms are much happier when they have full electron shells - like the noble gases in Group 0.

In most atoms, the outer shell is not full and this makes the atom want to react to fill it.