What is the absolute maximum number of electrons within a single atom that can simultaneously posses — Atomic Structure Chemistry Question

💡 Solution & Explanation

The third principal shell ($n=3$) consists of the $3s$ (1 orbital), $3p$ (3 orbitals), and $3d$ (5 orbitals) subshells, yielding a total of $n^2 = 3^2 = 9$ discrete orbitals. According to the Pauli Exclusion Principle, each orbital can hold a maximum of one electron with a spin quantum number $s = -1/2$. Therefore, the maximum number is $9 \times 1 = 9$ electrons.