What happens as you move down a group, in terms of shielding? Why?
a) Shielding decreases because electrons are added to the outer shells, increasing repulsion
b) Shielding increases because electrons are removed from the outer shells, decreasing repulsion
c) Shielding increases because electrons are added to the outer shells, decreasing repulsion
d) Shielding decreases because electrons are removed from the outer shells, increasing repulsion