Atomic Radius Trends can be found on Table S Trend from left to right (across a period) = DECREASES Trend from top to bottom (down a group) = INCREASES Ionic Radius *No table An atom that has gained or lost electrons will change in atomic size Metals lose electrons so ionic radius < atomic radius. Nonmetals gain electrons so ionic radius >atomic radius.
Ionization Energy The amount of energy required to remove the most loosely held valence electrons from a neutral atom. Trends can be found on Table S Trend from left to right (across a period) = INCREASES Trend from top to bottom (down a group) = DECREASES
Electronegativity The measure of attraction an atom has for a pair of electrons Trends can be found on Table S Trend from left to right (within a period) = INCREASES Trend from top to bottom (within a group) = DECREASES
Reactivity The transfer (gain or lose) of electrons Metals:more active toward the bottom left corner. Nonmetals: more active toward the upper right corner. Noble gases have no reactivity - why they weren't discovered for many years.
