The maximum number of electrons that can be accommodated in a shell is indicated by the formula:

Question

Question

This question was previously asked in

RRB ALP CBT I 31 Aug 2018 Shift 1 Official Paper

Answer 1

The correct answer is 2n2

Key Points

Shells are the orbitals or paths of different and definite energies in which the electrons revolve.
- They are represented as K, L, M, and N from lower to upper energies, where the innermost shell is the lowest and the outermost shell is the highest in terms of energy.
Each orbital is associated with a fixed number of electrons i.e., the maximum number of electrons present in s, p, d, and f subshells are 2, 6, 10 and 14.
The maximum number of electrons in a shell is given by 2n2. Hence option 2 is correct.
- That means n=1, 2, 3...for K, L, M, N....shell.

Additional Information

The outermost shell can have a maximum of 8 electrons whereas the penultimate shell cannot have more than 8 electrons until there are 2 electrons in the outermost orbit.
There must be 18 electrons in the penultimate shell and 2 electrons in the outermost shell for an atom to have more than 2 electrons.
For filling the orbit with 18 electrons, the inner orbital must be complete and the outermost and the penultimate orbit must have 2 and 8 electrons.