Please answer this physical chemistry problem. (The highest occupied level is mL=5)

4. (20 pt) The particle on a ring is a useful model for the motion of electrons around the porphine ring (see below). We may treat the group as a circular ring of radius 440pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. We assume that in the ground state of the molecule, each quantized energy level is occupied by two electrons. A) Calculate the energy and angular momentum of an electron in the highest occupied level