Maximum number of electrons that can be accommodated in shell with n=4 are:

Solution

Chemistry ma’am · 3 steps

Each shell holds 2n² electrons, so for n = 4 it is 2 × 16, not just n².

1. Count the orbitals. For n = 4, l can be 0, 1, 2 or 3, giving the 4s, 4p, 4d and 4f subshells. These have 1, 3, 5 and 7 orbitals, so the shell has 1 + 3 + 5 + 7 = 16 = n² orbitals.
2. Two per orbital. By the Pauli exclusion principle, each orbital holds at most 2 electrons with opposite spins.

   Nₘₐₓ = 2n² = 2 × 4² = 32

3. So. The shell with n = 4 can hold at most 32 electrons, option (b).

The idea to keep. A shell has n² orbitals and each orbital takes 2 electrons, so the shell holds 2n² electrons. Do not mix this up with the 2(2l+1) count for a single subshell.

Answer from the NTA final answer key. Solution by PrepWiser.