The atomic number of He is 2.
So, it has two protons and two electrons.
The electron distribution for two electrons is 1 s^2.
That means that both electrons are in the orbital 1 s when they are in ground-state (not excited).
So, the quantum numbers are:
n = 1
l (lower case L) = 0
ms = 0
s = -1/2 and 1/2
So these are the two set of quantum numbers:
(1, 0, 0, +1/2), and (1, 0, 0, -1/2)
