1. The problem statement, all variables and given/known data From quantum numbers: n=2, l=1, m=-1 find the total energy, Lz and L^2? 2. Relevant equations E = -Er/n^2 (I think, although it refers to the total energy we have the principle quantum numbers so I'm good to go. Lz = mh(bar) L^2= l(L+1)(hbar)^2 3. The attempt at a solution E = -3.4eV (Just from plugging numbers) Lz = - hbar L^2 = 2(hbar)^2 (apologies for hbar - I don't know how to write it nicely. It's just planks constant divieded by 2pi) However I can't find units for the Lz, or the L^2. Am I being incredibly stupid, and it the hbar the unit - or is there is there a uni? I have searched on hyperphysics and in three text books for this - and none give a unit, or a justification as to why there is now one. Thanks.