The vertical column in the periodic table is called a group.

The horizontal row in the periodic table is called a period.

Atomic radius is the distance between the nucleus of the atom and its outermost shell.

The tendency of a metal atom to form a cation by losing its valence electron(s), is called electropositivity of that element.

The tendency of a non-metal atom to form an anion by accepting electron(s), is called electronegativity of that element.