How do you find the charge of certain compounds? Like CrI3

Question

How do you find the charge of certain compounds? Like    CrI3

anonymous · Answer

You must use the periodic table to figure out the group it's in.

anonymous · Answer

im not sure if you are trying to find the "formal charges" for this but if you are then you have to draw the lewis structure and then use the formula:
 # valence electron of the atom - lone pairs - # bonds = formal charge

for example look at the lewis structure of water ( H2O )
if you want to know the charge of Oxygen then follow the formula:
6 -> valence electrons of oxygen
4 -> dots (lone pairs) 
2 -> the number of bonds (with hydrogen)

therefore:
6-4-2 = 0 
so oxygen has a zero charge

I hope this was what you looking for and I helped you :D 

Good luck!!!