Of the elements in group 13 (3a) , predict which has (a) the largest atomic radius (b) the largest electronegativity, and (c) the smallest ionization energy. explain your predictions yahoo answers

(a) the largest atomic radius: atomic radius is the same as atomic size. 
This term refers to the distance from the center of the atom's nucleus to the outermost shell of electrons. The atomic radius increases longitudinally from the right of the periodic table to the left, meaning that the group with less radius is the 18 and the first group has the biggest radius. The radius also increases  vertically from superior to inferior. Meaning that the elements more superior on periodic table have less radius, while the ones lower have more radius.
Nihonium

b) the largest electronegativity: is a property that describes the tendency of an atom to attract electrons towards itself. This property increases longitudinally from the left of the periodic table to the right, meaning that the group with more electronegativity is the 18, while the first group has the less eletronegativity. It also increases  vertically from inferior to superior. Meaning that the elements more superior on periodic table have more eletronegativity, while the ones lower have less.
Boron

c) the smallest ionization energy: Ionization energy is the opposite of eletronegativity, meaning that its the energy required to remove an electron from a neutral atom. The ionization energy increases from left to right, meaning that the group with more of this energy is the 18, while the first group has the less. It also increases from the bottom to the top of the periodic table.
Boron

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