1. Francium is the largest atom because as you go down the columns the atoms will become larger; as you go right to left the atoms also increase in size. Francium also has the largest atomic radi among the other atoms, it has the most protons and neutrons in its nucleus. This atom has the lowest ionization because Francium has the most of seven energy shells, the nucleus can not hold onto its valence electrons as strongly as Fluorine could. Due to the size of its atomic radi the attraction of the valence electron to the nucleus is weak. Therefore it does not take a lot of ionization energy to take the electron away from any large atom, such as Francium. This same idea follows for the electronegativity of Francium because the pull of the valence electron is not strong. Francium does not need a lot of energy to gain an electron.
2. Helium is the smallest atom because it is the atom in the top right corner of the periodic table. On the periodic table in each column the atom on the very top is the smallest and as you go from left to right the atoms will eventually appear to be smaller. Helium, a noble gasses, also has the smallest atomic radi which means the full shell of eight valence electrons is strongly pulled towards the nucleus. Noble gasses have a full shell of eight electrons, they do not attempt to gain or loose and electron.
3. The Noble Gasses don't have a large EN value because all the atoms in the far right column already have a full shell of valence electrons. These atoms do not try to gain or loose any electrons because they want to stay at an nonreactive state.
4. Fluorine has the highest EN because it's the smallest atom (not including the Noble Gasses) that has the smallest number of protons and neutrons. therefore because Fluorine only has two shells the pull form the nucleus to the electrons is strong. Meaning because Fluorine is a metal and because it is small it really wants to gain one more electron to become a non reactive metal.
