What can electrons hold

Each shell can contain only a fixed number ofelectrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2 (n2) electrons.

One can only hold 2 electrons which only means shell two can hold 8, and for the first eighteen elements shell three can hold a maximum of eight electrons