# How many valence electrons do group one have?

Aug 9, 2016

#### Explanation:

Group I elements have one valence electron on their outer shell. This is the main reason why their are placed in group I.

Let us take a look on the electron configuration on some of these elements:

""_1H: 1s^1
""_3Li: 1s^(2)2s^(1)
""_11Na: 1s^(2)2s^(2)2p^(6)3s^(1)
""_19K: 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(1)
""_37Rb: 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(10)4p^(6)5s^(1)

As you can notice, the electron configuration of all these elements end with $\textcolor{b l u e}{n} {s}^{\textcolor{red}{1}}$, where $\textcolor{b l u e}{n}$ represents the outer shell, and the number $\textcolor{red}{1}$ indicates that there is only one valence electron in these elements.