1. Lithium, water, edible salt, chalk, Carbon, Lime, Nitrogen, Potassium, Oxygen, Iodides, Iron, Chlorine, etc are some matters.

(a) Expressing the matters of the stem by symbol and formula separate the elements
and compounds. ---3 marks

Explanation:

An atom is the smallest unit of an element that can take part in a chemical reaction. Atoms (and there corresponding symbols) mentioned in the question are

Lithium ⇒ Li

Carbon ⇒ C

Nitrogen ⇒ N

Potassium ⇒ K

Oxygen ⇒ O

Iron ⇒ Fe

Chlorine ⇒ Cl

A compound is substance that contains two or more atoms that are chemically combined and can be represented with a chemical formula. The compounds (and there corresponding formula) mentioned in the question are

Water ⇒ H₂O

Edible salt (sodium chloride) ⇒ NaCl

Chalk (calcium carbonate) ⇒ CaCO₃

Lime (calcium oxide) ⇒ CaO

Iodides (such as sodium iodide and potassium iodide) ⇒ NaI and KI respectively