Question

Mention the factor that decides the number of elements in I, II, III and IV period. What is the number of elements in second and third period?

Answer 1

1. the maximum number of electrons present in a shell is given by the formula 2n², where 'n' is the orbit number or energy level index 1,2,3....
hence maximum number of electrons are as follows:
K shell- 2×1²=2
L shell- 2×2²=8
M shell-2×3²=18
N shell- 2×4²=32

2. the maximum number of electrons they can be accommodated in the outermos orbit is 8.

3.electrons are not accommodated in a given shell, unless the inner shells are filled i.e the shells are filled in a stepwise manner.