Chemical Formula Name of Compound Type of Compound?

Hi! I need to know if I'm right on this for an upcoming test this Thursday! I'm given the chemical formula and have to know the rest, would you let me know if I'm right or not on this stuff? The professor said not to use any prefixes or ite's or ate's for this test. Thanks in advance!! NaF = I think it is... show more Hi! I need to know if I'm right on this for an upcoming test this Thursday! I'm given the chemical formula and have to know the rest, would you let me know if I'm right or not on this stuff? The professor said not to use any prefixes or ite's or ate's for this test. Thanks in advance!!
NaF = I think it is Sodium Floride and it is an Ionic Compound
C3H8 = propane and is Covalent
BaCl2 = Barium diChloride and is Ionic
Ba3P2 = Barium diphosphide and is Ionic
NaO2 = Sodium Oxide and is covalent
P8I3 = Phosphorous Iodide and is Covalent
NH3 = Nitrogen Hydride and is Covalent
Na2S = Sodium Sulfide and is ionic

Now for this next set he gave us the Name of the compound and I have to figure out the chemical formula and the type of compound.
Sodium Oxide = Na02 = Covalent
Trisulfur Dioxide = S302 = Covalent
Pentane = C5H12 = Covalent
Calcium Nitride = CaN2 = Ionic
Potassium Carbide = KC = Ionic

I really get messed up on knowing how many goes at the end of a combined formula. I just hope I can figure this out before Thursday!
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