# How many valence electrons does zinc have?

Jun 17, 2015

You take a look at its electron configuration.

#### Explanation:

Zinc is located in period 4, group 12 of the periodic table and has an atomic number equal to 30.

This means that neutral zinc atom has a total of 30 electrons surrounding its nucleus. To see how many of these electrons are valence electrons, write the electron configuration of a neutral zinc atom.

$\text{Zn} : 1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2} 3 {d}^{10}$

or, if you use the noble gas shorthand notation

"Zn": ["Ar"] 4s^2 3d^10

Notice that the outermost shell, which for zinc is the fourth shell, $\text{n=4}$, has two electrons.

This means that zinc can lose the two electrons located in the 4s-orbital to be become the $Z {n}^{2 +}$ cation.

"Zn"^(2+): ["Ar"] 3d^10

Notice that the 3d-orbital is completely filled, which means that these electrons behave like core electrons and cannot be considered valence electrons.

Therefore, zinc has only 2 valence electrons, both located in the 4s-orbital.