Question

how many valence electron(s) do element (electron configuration: 1s²2s²2p⁶3s²) have? a 10 b 3 c 6 d 2

Explanation:

Step1: Identify valence shell

Valence electrons are in the outermost shell. Here, the outermost shell is \(3s\).

Step2: Count electrons in valence shell

The electron configuration of the outermost shell is \(3s^{2}\). The exponent \(2\) indicates the number of electrons.

Answer:

D. 2