2. Given the chemical formulas of the following compounds, name each compound and state the rules you used to determine each name. • KI
• Fe2O3
• (NH4)3PO4

Explanation:

KI:

The name of salt consist of two parts. The first part is the name of metal and second is the name of nonmetal.

So we name the cation first and then anion.

IN given formula cation is potassium while anion is iodine.

The -ine of anion is converted into -ide. Thus the name will be potassium iodide.

Fe₂O₃

First of all we will write the name of cation and then anion.

               Iron    oxygen

Then the we will add -ide at the end of name of anion such as, oxide, chloride, fluoride etc.

               Iron oxide

Now we will calculate the charge on oxygen and iron. We know that the charge on oxide is -2 and thus the total charge on oxygen is 3(-2) = -6. Thus iron must have +3 oxidation state to cancel the charge and make compound neutral. It means 2(+3) = +6

The oxidation state of transition metal will be written in parentheses.

               Iron(III) oxide

(NH₄)₃PO₄

To write the name we must know which is cation and which is anion.

In given formula NH₄⁺ is cation and it carry +1 charge while PO₄³⁻ is anion and it carry -3 charge.

When we write the name we write first the name of cation and then anion.

Here the cation name is ammonium while anion name is phosphate thus the name of compound is ammonium phosphate.

In order to make the compound neutral the opposite charges must be equal to cancel each other.

That's why three ammonium ions are attached with one phosphate ion to make the compound neutral.