im a doing double displacement lab and one of the solutions that im working with is Copper Sulfate. on the labsheet that my teacher gave me, it's written as CuSO4 (the 4 is a subscript). but from my knowledge, because sulfate has a charge of -2, shouldnt it be Cu2SO4 (with all #'s subscripts). if not, can i have an indepth explanation as to why it's not
CuSO4. Actually it is often hydrated, then it's CuSO4.5H2O.
Copper is a transition metal - it is not in any group. One of the properties of a transition metal is variable valency. This means that they can have different charges. So, for example, Iron Oxide can be FeO (where iron has a valency of two and therefore it is written Iron (II) Oxide) or Fe2O3 (where iron has a valency of three and therefore it is written Iron (III) Oxide). Anyway, back to your question. In the case of copper sulphate, we find that it is always copper (II) sulphate, so that makes it CuSO4, where the Cu has a 2+ charge. The reason for this is that of the two possible oxidation states, 1+ and 2+ (3+ and 4+ do occur but are very rare), 1+ is less stable and can only form compounds with the halides and oxygen. Most other common copper compounds are 2+.
