# How many valence electrons does Cr have?

Jun 28, 2017

Surely there are 6..........?

#### Explanation:

Chromium lies in Group 6 of the Periodic Table; i.e. there are 6 valence electrons.......

Given $C r$, $Z = 24$, we could write the $\text{d-electron configuration}$ as follows......

$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2} 3 {d}^{4}$

At undergraduate level you learn that the electron configuration is actually........

$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{1} 3 {d}^{5}$

(the half-filled $4 s$ and $3 d$ orbitals lend an extra stability!)

But in either configuration there $\text{SIX VALENCE ELECTRONS...}$