# How do electron configurations in the same group compare?

Feb 1, 2014

The electron configurations of elements in the same group (column) of the periodic table are the same.

The Alkalai Metals are found in the first column of the periodic table Group IA. This set of elements all have valence electrons in only the 's' orbital and because they are in the first column they all has ${s}^{1}$ orbital configurations.

H $1 {s}^{1}$
Li $1 {s}^{2} 2 {s}^{1}$
Na $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{1}$
K $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{1}$

If we look at the other side of the periodic table and look at Group 17 known as the Halogens, the pattern of the electron configuration holds consistent as each of these elements are in the fifth column of the 'p' block of the periodic table.

F $1 {s}^{2} 2 {s}^{2} 2 {p}^{5}$
Cl $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{5}$
Br $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2} 3 {d}^{10} 4 {p}^{5}$