In chemistry terms the difference between radical and molecule
is that
radical is a group of atoms, joined by covalent bonds, that take part in reactions as a single unit while
molecule is the smallest particle of a specific element or compound that retains the chemical properties of that element or compound; two or more atoms held together by chemical bonds.
As nouns the difference between radical and molecule
is that
radical is a member of the most progressive wing of the Liberal Party; someone favouring social reform (but generally stopping short of socialism) while
molecule is the smallest particle of a specific element or compound that retains the chemical properties of that element or compound; two or more atoms held together by chemical bonds.
As an adjective radical
is favoring fundamental change, or change at the root cause of a matter.