What is the maximum number of electrons that can be identified with the following set of quantum numbers? n=4, l=0, ml=0, ms=+1/2

Answer 1

These 4 quantum variables describe an electron in an s orbital in the 4th shell of an atom. Given that only 2 electrons may occupy any orbital, and electrons in any orbital must have opposite spin states, once the +1/2 spin rate is defined for one of the electrons, the other electron must have an opposite spin state (ms=-1/2). So in effect, only 1 electron in this particular orbital may have these quantum values. The other will be:

n=4

l=0

ml=0

ms=-1/2

See Pauli Exclusion Principle

Answer 2

n = 4: 4th shell

l = 0: s subshell

ml = 0: s orbital

ms = +1/2: spin

This can identify ONLY 1 electron, as no 2 electrons can have the same 4 quantum numbers.