Question

What are the number of electrons in the dofferent number of shells ?

Answer 1

First, we look at the n=1 shell (the first shell). It has:

• The 1s orbital

An s-orbital holds 2 electrons. Thus n=1 shell can hold two electrons.

The n=2 (second) shell has:

• The 2s orbital
• The 2p orbitals

s-orbitals can hold 2 electrons, the p-orbitals can hold 6 electrons. Thus, the second shell can have 8 electrons.

The n=3 (third) shell has:

• The 3s orbital
• The 3p orbitals
• The 3d orbitals

s-orbitals can hold 2 electrons, p-orbitals can hold 6, and d-orbitals can hold 10, for a total of 18 electrons.

Therefore, the formula 2n22n2 holds!