I am working with cations, and anions. Are you supposed to have the subscripts balance, or the top numbers? Or both? Why would a cation of AL +3( upper corner) and an anion of PO -3 in the upper corner 3 as the subscript become a compound of AlPO3(subscript). I see how Al shouldn't have any numbers by it, but I don't see why PO should have a three as a subscript. Why is that? Thank you for your help.

Question

I am working with cations, and anions.  Are you supposed to have the subscripts balance, or the top numbers? Or both? Why would a cation of AL +3( upper corner) and an anion of PO -3 in the upper corner 3 as the subscript become a compound of AlPO3(subscript). I see how Al shouldn't have any numbers by it, but I don't see why PO should have a three as a subscript.  Why is that? Thank you for your help.

Chopsticks · Answer

If the superscript (top number) is balance, then you don't have to do anything with the subscript.

Since Al has a +3 charge and PO has a -3 charge yout going to have to make it neutralize it.

Al^3(PO-)3 The first 3 is on top and the second 3 is on the bottom. I put paranthises around the PO- because its polyatomic

Ok now, Since Al^3 has a +3 charge, PO- will need a subscript of 3 to make it neutralize. 3-3 = 0

Chopsticks · Answer

Sorry typo:

Since Al has a +3 charge and PO has a -3 charge yout going to have to make it neutralize it.

Should be:

Since Al has a +3 charge and PO has -1 charge yout going to have to make it neutralize it.

Ms. Sue · Answer

you're not "yout"

DrBob222 · Answer

An easier way is to look at the site I gave you in another post and you notice phosphate is PO4^-3. Now, since all compounds are zero, AlPO4 is the formula for aluminum phosphate BECAUSE Al is +3 and PO4 is -3 and +3 and -3 = 0.