Question

How many valence electrons do group one have?

Answer 1

One valence electrons.

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 `color(blue)(n)s^(color(red)(1))`, where `color(blue)(n)` represents the outer shell, and the number `color(red)(1)` indicates that there is only one valence electron in these elements.