Francium is the biggest element with the lowest Ionization Energy and ElectroNegativity because it has many shells which are layered together loosely. The Valence e- are on the outermost shell so it can not hold on to its e- very tightly. It is the biggest because it has the most shells(7). Its nucleus is the farthest from its outermost shell is not strong enough to easily pull e- away.
Why Helium is the smallest element with the highest IE:
Helium is the smallest element because it has only one shell. It has the highest Ionization Energy because it is closest to its Valence e- and attracts them the most.
Why Noble Gases don't have EN values:
Noble Gases do not have Electro-Negativity values because they are unreactive. They have a full Valence Electron shell and cannot react for any more electrons and therefore have an undefined EN.
Why Fluorine has the highest EN:
Fluorine has the highest EN because it has two shells and seven Valence e-. It has high Ionization Energybecause its Electrons are really close to its Nucleus and it has a very small size and short distance between shells.
