how many electrons can n=4 l=1 have?

Answer 1

m_l can be +l to -l in increments of 1 including zero. So
-1, 0, +1 and each m_l can have two electrons in with m_s being +1/2 or -1/2. That looks like 6 to me. There's an easier way to do it. if l = 1 that is a p electron and we all know we can have 6 p electrons.