By: Elizabeth, Keara, Jimmy, and Louis
Group: As you move to the down the atomic radius Increases.
Period: As you move to the right the atomic radius decreases.
As you move down the atomic radius increases.
Reason: There is a jump in size of the nucleus (protons +neutrons ) when going down in groups. New energy levels of elections clouds are added to the atom when moving down in groups. This increases the mass and volume of the atom by a lot.
As you move to the right the atomic radius decreases.
Reason: There are stronger attractive forces in atom (as you go left to right). Which causes them to group closer together, resulting in shrink of the atom.