What would the fourth quantum number of a 1 S 2 electron be?

Answer 1

Either +1/2 or -1/2; the fourth quantum number is ALWAYS either +1/2 or -1/2 and it's not generally possible to say which (other than that two electrons in the same atom which have the same first three quantum numbers will always have different values for the fourth).

Answer 2

The fourth quantum number is the electron spin quantum number, denoted by (m_s). For a 1S orbital with 2 electrons, the electron spin quantum numbers of the two electrons would be (m_s = +\frac{1}{2}) and (-\frac{1}{2}) according to the Pauli exclusion principle.

Answer 3

n = 2, l = 0, ml = 0, ms = -1/2

Answer 4

n = 4, l = 2, ml = -1, ms = +1/2

Answer 5

n = 3, l = 1, ml = -1, ms = +1/2

Answer 6

n (principle quantum number) = 2

l (angular momentum quantum number) = 0

ml (magnetic quantum number) = 0

ms (spin quantum number) = +1/2 or -1/2