Question

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

Answer 1

The name of compound
`KI` is, potassium iodide.

The name of compound
`Fe_2O_3` is, iron (III) oxide.

The name of compound
`(NH_4)_3PO_4` is, ammonium phosphate.

Explanation :

Ionic compound : It is a type of compound that is made up of the ions of the two different elements in which one element is a metal and another element is a non-metal.

The rules of ionic compounds is given by:

• Positive ion is written first.
• The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
• In case of transition metals, the oxidation state are written in roman numerals in bracket in-front of positive ions.

(1) The given compound
`KI` is an ionic compound. It is made up of two different ions which are potassium ion
`(K^+)` and iodide ion
`(I^-)`.

So, the name of
`KI` is, potassium iodide.

(2) The given compound
`Fe_2O_3` is an ionic compound. It is made up of two different ions which are iron ion
`(Fe^(3+))` and oxide ion
`(O^(2-))`. In this an oxidation state of iron is (+3).

So, the name of
`Fe_2O_3` is, iron (III) oxide.

(3) The given compound
`(NH_4)_3PO_4` is an ionic compound. It is made up of two different ions which are ammonium ion
`(NH_4^+)` and phosphate ion
`(PO_4^(3-))`.

So, the name of
`(NH_4)_3PO_4` is, ammonium phosphate.

Answer 2

KI is the chemical formula of potassium iodide. KI is a white solid salt under room temperature and pressure. Fe2O3 is the chemical formula of iron (III) oxide is a red-brown solid that exists under normal conditions. (NH4)3PO4 is called ammonium phosphate. This is a really unstable salt with no commercial value.