How many valence electrons does nickel have?

Nickel has eight electrons in the 3d orbital and two electrons in the 4s orbital, which means nickel has 10 total valence electrons. The reason it has 10 is because nickel is a transition metal, so the d and s electrons can participate in chemical bonding.

Valence electrons are the electrons of an atom that can participate in chemical bonding. Because nickel is a transition metal, the classic method of determining the number of valence electrons doesn't work. Instead, a modified d electron count method is used. For nickel, electrons in the outer two orbitals can participate in chemical bonding, which means nickel has 10 valence electrons in total.