How many electrons can have the quantum numbers n 5 ℓ 0 ml0?

Answer 1

There can be two electrons with those quantum numbers in an atom. Each electron is completely described by four quantum numbers. The one that's missing in the list provided is ms, which can have only two possible values (+1/2 and -1/2).

Answer 2

The quantum numbers n = 5, ℓ = 0, and ml = 0 correspond to the 5s orbital. The maximum number of electrons that can occupy the 5s orbital is 2.