(a) The chemical formula of a compound is a symbolic representation of its composition. The combining power or combining capacity of an element is known as its valency. Valency can be used to find out how the atoms of an element will combine with the atom(s) of another element to form a chemical compound. Some elements show more than one valency.

While writing the chemical formulae for compounds, we write the constituent elements or their symbols and their valencies as shown below. Then we must crossover the valencies of the combining atoms. The positive and negative charges must balance each other and the overall structure must be neutral.

In magnesium chloride, there will be two chloride ions per one magnesium ion. Thus, the formula or magnesium chloride is MgCl₂

(b) The chemical formula of a compound is a symbolic representation of its composition. The combining power or combining capacity of an element is known as its valency. Valency can be used to find out how the atoms of an element will combine with the atom(s) of another element to form a chemical compound. Some elements show more than one valency.

While writing the chemical formulae for compounds, we write the constituent elements or their symbols and their valencies as shown below. Then we must crossover the valencies of the combining atoms. The positive and negative charges must balance each other and the overall structure must be neutral.

Thus, the formula of Calcium Oxide is CaO.

(c) The chemical formula of a compound is a symbolic representation of its composition. The combining power or combining capacity of an element is known as its valency. Valency can be used to find out how the atoms of an element will combine with the atom(s) of another element to form a chemical compound. Some elements show more than one valency.

While writing the chemical formulae for compounds, we write the constituent elements or their symbols and their valencies as shown below. Then we must crossover the valencies of the combining atoms. The positive and negative charges must balance each other and the overall structure must be neutral.

Thus, the formula or copper nitrate is Cu(NO₃)₂

(d) The chemical formula of a compound is a symbolic representation of its composition. The combining power or combining capacity of an element is known as its valency. Valency can be used to find out how the atoms of an element will combine with the atom(s) of another element to form a chemical compound. Some elements show more than one valency.

While writing the chemical formulae for compounds, we write the constituent elements or their symbols and their valencies as shown below. Then we must crossover the valencies of the combining atoms. The positive and negative charges must balance each other and the overall structure must be neutral.

In Aluminium Chloride, there are three chloride ions per one aluminium ion. Thus, the Aluminium chloride is AlCl_3.

(e) The chemical formula of a compound is a symbolic representation of its composition. The combining power or combining capacity of an element is known as its valency. Valency can be used to find out how the atoms of an element will combine with the atom(s) of another element to form a chemical compound. Some elements show more than one valency.

While writing the chemical formulae for compounds, we write the constituent elements or their symbols and their valencies as shown below. Then we must crossover the valencies of the combining atoms. The positive and negative charges must balance each other and the overall structure must be neutral.

Thus, the formula or calcium carbonate is CaCO₃