The electron configuration for gallium (Ga), which has an atomic number of 31, is 1s² 2s² 2p⁶ 3s² 3p¹. This means that gallium has a total of 31 electrons arranged in various energy levels around the nucleus.
To determine the number of valence electrons, we focus on the electrons in the outermost shell. For gallium, the outermost shell is the third energy level, which has the following configuration: 3s² 3p¹. Adding these together, gallium has a total of 3 valence electrons.