Which element has quantum numbers 3 1 0 -1/2

The element is Aluminium. (assuming that the given quantum number set is for the valence electron of the unknown element)

Explanation:

The given quantum numbers are:

n=3 (Principal Quantum Number)

l=1 (Azimuthal Quantum Number)

m=0 (Magnetic Quantum Number)

s= -1/2 (Spin Quantum Number)

The given set of quantum numbers refer to the 3p orbital.

Assuming that this the valence electron of the element, the unkown element is Aluminium.

im pretty sure its b

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a