# An element with an electron configuration of 1s^2 2s^2 2p^6 3s^1 will have properties most similar to which element?

May 17, 2018

sodium (Na)

#### Explanation:

Given: electron configuration $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{1}$

The periodic table can generally be used to find the electron configuration of an element. There are a few special cases:

1st column, hydrogen + alkali metals: $1 {s}^{1}$

2nd column, alkaline earth metals: $1 {s}^{2}$

3rd-12th columns, transition metals: ${d}^{1} \to {d}^{6}$

13th-18th columns, Boron - neon: ${p}^{1} \to {p}^{6}$

Inner transition metals: ${f}^{1} \to {f}^{14}$

Look at the last set of electrons (valence) in your example: $3 {s}^{1}$

This means the element falls within the column 1: alkali metals. The $3$ represents the number of energy levels (periodic table row).

This means $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{1}$ = the electron configuration for sodium (Na).