Hi can someone help me with these 2 :)

In the millikan oil drop experiment they determined that every drop had a charge which was a while number multiple of -1.60x10^-19. if a drop has a total charge of -9.60x10^-19 then how many excess electrons are contained within the drop?

Name the intersection of plane bpq and plane cpq.

Will mark brainliest how many electrons can be held in the energy level n = 4?