Question

Without using a periodic table, give the full ground-state electron configuration and block designation (s−, p−, d−, or f−block) of an atom with:

a) 14 electrons

b)19 electrons

c) 32 electrons

Answer 1

s-orbital can accomodate a maximum of 2 electrons, p can accomodate 6 and d can accomodate 10 electrons

Electrons are filled into the atomic orbitals in the following order:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d

This means 1s orbital is fully filled upto its capacity before proceeding to 2s, and so on.

One thing to remember is that whenever there is a chance to make any orbital half full, it is given preference.

(a) 14 electrons: 1s² 2s² 2p⁶ 3s² 3p²

(b) 19 electons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

(c) 32 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p²