Write formulas for the compounds that form from Sr and each of the following polyatomic ion: NO3 −1, SO4 −2, PO4 −3.

Question

SR (+3 CHARGE)

NO3(-1 CHARGE)
SO4(-2 CHARGE)
PO4(-3 CHARGE)

Re posting this question. hopefully someone can help me answer this now. Please answer to this question.

Answer 1

Here is how you do a couple of them. Then you try the others.
Sr and NO3^-1
Sr is a +2 charge. There is no Sr with a +3 charge.
Sr(NO3)2. You can see Sr is +2 and 2 NO3^- is -2 so the +2 neutralizes the -2. All compounds will be zero charge and that's how you know what numbers to use for each ion. For the sulfate (SO4^2- it is SrSO4. The easy way to do this is to write the ions down like this
SrNO3. Place the +2 charge over the Sr and the -1 charge over the NO3. Now DRAW and X (mentally) with the left diagonal over the Sr at the top and the bottom of the left diagonal under the NO3^-. The right diagonal is done the same way with the top over the NO3^- and the bottom under the Sr. Move the numbers down the diagonal at the top to the bottom of THAT diagonal; i.e., the 2 moves the the bottom right (which means 2 NO3^-) and the 1 moves to the bottom left (which means 1 for Sr). Ignore the signs. You need not write the 1 (that's understood) and if the numbers you get (like SrSO4 would be Sr2(SO4)2, reduce those to the smallest numbers; i.e., 1 so SrSO4 is what you end up with. Hope this helps. I shall be happy to check your answers or answer any questions.

Answer 2

i posted my work in the original posting

Answer 3

But you know those answers are wrong. You should follow my rules above to get the correct answers.