chemisty work

1. Write a formula for the compound that forms from each pair.

a) Aluminum and sulfur


Aluminum = Al³⁺ Sulfur= S^2-
=Al₂S₃

b) Beryllium and iodine
Beryllium = Be²⁺ Iodine= I^-
=BeI₂
c) Calcium and phosphate

Calcium= Ca² ???????????

d) Sodium and Oxalate.

I am having a hard time figuring out how to get phosphate and oxalate because they are not on the chart

Phosphate is PO(4) (3-) charge, and Oxalate is C(2)O(4) (2-). I assume you mean they are not on the periodic table - this is true because they are not elements, but are polyatomic ions.