what is the different between ionic and molecular

actually ionic compound does not necessarily contain metal and non-metal.

OK, in a microscopic view, a molecule is a species making up of one or more atom such that there is no point in-between the two nucleus that the electron density is zero.
it sounds very difficult. Let me explain using H2O. a H2O molecules is made up of 2 H atoms and 1 O atom. A covalent bond is formed between them. due to sharing of electron, there is not a point between H and O atom such that electron density is zero. i.e. There is always some electron in between H and O

if the above statement does not hold, the species is ionic.

do you mean ionic compound and molecular compound?
ionic compound is a compound with a metal + a non-metal