Ionization energy is the amount of energy required to remove an electron from a gaseous atom or ion.
Ionization Energy cheat sheet for homework
This is the amount of energy released when an electron is added to a neutral atom to form a negative ion.
These are electrons that reside in the outermost shell surrounding an atomic nucleus and can participate in chemical reactions.
This refers to the size of an atom, typically measured by the distance from its nucleus to its outermost electrons.