The formula of copper sulfide is CuS but the formula of copper sulfate is CuSO4. State and explain the names of the compounds with the formulae Na3P and Na3PO4. Na3P: Na3PO4: explanation:

Na3P is Sodium phosphide

Na3PO4 is sodium phosphate

Explanation:

Na3P is a combination of the element sodium

and the element phosphorus.

When writing the chemical formula of compounds, we have to take into consideration the valencies or combining powers of the individual parties, whether single elements or radicals

Under general terms, the valency of sodium is - + 1 and its combining form can be written as Na+. While in the case of phosphorus, its own is - 3 and its form is P3-.

Now, to write the chemical formula, there has to be an exchange of valencies by the two elements in question. That is why finally, sodium took 3 and phosphorus took 1 and we have Na3P.

Now, for the name phosphide, phosphides are binary compounds that contain phosphorus and a metal. When we talk of binary compounds, we mean compounds that have two elements only. So because sodium is a metal, we have to give the name phosphide to the compound.

Na3PO4

Referencing the explanation made above, but this is a bit different. We have sodium coming in contact with a radical here. The combination it is making here is with the phosphate ion (PO4) 3-.

So as usual, there is an exchange of valency and thus sodium takes the 3, while the whole phosphate group take 1. So therefore, the name of the compound is gotten from the combination of the individual parties and it is called sodium phosphate.