Binary Ionic compound contain a metal and a non-metal. While molecular (covalent) compounds contain two non-metals.
For ionic compounds the metal always keeps its name while the non-metal will keep the root of the element with the suffix -ide.
Na = sodium Cl = chlorine
Keep the metal name sodium, take the root of chlor and add -ide.
Ca = calcium F = fluorine
Keep the metal name calcium, take the root fluor and add -ide.
For molecular (covalent) compounds the number of atoms in each molecule is identified by a prefix in the name. The second element will always end in the suffix -ide.
di = 2
tri = 3
tetra = 4
penta = 5
hexa = 6
hepta = 7
octa = 8
nona = 9
deca = 10
Never use mono with the first element.
C = carbon O = oxygen = oxide
N = nItrogen Cl = chlorine = chloride
P = phosphorus O = oxygen = oxide
(drop the a from the prefix when using oxide)
I hope this was helpful.