# What is the ground-state electron configuration of a neutral atom of copper?

For copper, $Z = 29$...
$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{1} 3 {d}^{10}$
The $d - \text{orbital}$ filling is anomalous. Depending on where you are (A level; 1st year; 2nd year?), it simply has to be known.