Question

how many valence electrons does calcium have?

Explanation:

Step1: Determine the electron configuration of calcium

Calcium has an atomic number of 20. Its electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}\).

Step2: Identify the valence electrons

Valence electrons are the electrons in the outermost shell. For calcium, the outermost shell is the 4th shell (\(n = 4\)), and there are 2 electrons in the \(4s\) orbital.

Answer:

2