d orbital electrons

[Grace Chen 3F]

Does electrons in d orbital count as valence electron? For example, does [Ar] 3d1 4s2 have 3 or 2 valence electrons?

[Arya Bhalla 1H]

Valence electrons are in the outermost shell, so in this case there would be 2 valence electrons because the outermost shell has an n-value of 4, and there are only 2 electrons here that have n equal to 4.

[Grace Chen 3F]

I asked my TA today, and she says that because e- in both ns orbital and (n-1)d orbitals are involved in reactions, so d orbital electrons do count as valence electron (e.g. [Ar] 3d1 4s2 has 3 valence electrons).