How can you tell if a compound is ionic or covalent? and why

so we are learning about ionic and covalent compounds, and what I just don't get is WHY its ionic or covalent!
an example!
CaCl2 is ionic...
WHY!?

ok covalent is where the valence electrons share a bond. like water and oxygen in H²O and an ionic bond is where the electron is transfered to the other chemica when really only happens with 1- 7 valence electrons or when it adds up to 8. so is it CaCl²? cause if it is then its an ionic bond

In order to determine what it is one must look at the electro negativity of the elements in the compound. Electro negativity is a measure or an atoms ability to draw electons to itself. A version of the periodic table with it on must be consulted. In order to determine whether a compound is ionic or covalent, take the difference of the two. If the number is less than 1.7, then it is covalent. If it is greater then it is ionic. Its as simple as that. Of course, there are some exeptions in the metals because they basically always ionically bond.

I'll make it simple for you. If it's ionic, it's a metal and a nonmetal-- in other words one's from the right side the other from the left. Now if you have a compound where the elements are found both in the right side, that's covalent. If it's double right, it's metallic.

Ionic is non-metal to metal with the exception of Hydrogen to a non-metal then it's covalent. Covalent is non-metal to non-metal. This is a very basic answer and there are always exceptions.