What are the ionic compound formulas for these cations and anions?

chemistry is a hard science but if you follow these rules you will be able to find formulas very easy

1. metals generally form cations, nonmetals anions

2. the metal (or cation such as ammonium NH4+) always go first in the formula

3. once you write the formula you need to balance the charges (i'll go over this more)

4. reduce to the simplest whole number ratio unless you have a polyatomic ion (pai), never break up a polyatomic ion or a complex ion

okay lets go

the formula for 1 would start off as AlCO3, but you need to balance the charges

the trick is that the charge of the anion is the number of cations you will have and vice versa

the formula would be Al2(CO3)3

the () are used to show that you have 3 moles of the CO3 -2 in the compound, you only use them on a pai

the charge of Al would therefore be 2(3+) or 6+ and the charge of CO3 would be 3(2-) or 6- making a neutral compound

here are you other answers

2. ALCl3 (note that you never write a one and no () are used on the chloride ion)

3. Al(OH)3

4. AlPO4 (notice that there's no need for Al3(PO4)3 because it reduces)

5.CaCO3

6. CaCl2

7. Ca(OH)2

8. Ca3(PO4)2

sorry this was such a long answer but i hope this helps