Angular momentum of an electron in an orbital of an atom (L)=mvr To find out the units, L=mv×r=kg×ms−1×m L=kgm2s−1.....(i) We know that, 1 Joule =kgm2s−2 Multiplying and dividing Eq. (i) by s−1 L=kgm2s−1×s−1∕s−1 =kgm2
s−2
s−1
L=J−s Hence, the unit for angular momentum of an electron in an orbital is J−s.