Question

What are the formulas for the following ionic compounds: sodium sulphide, caesium bromide and magnesium nitride?

Answer 1

The chemical compounds that comprise ions and are held together with the help of electrostatic forces named ionic bonding are known as ionic compounds. These compounds are formed of cations (positively charged ions) and anions (negatively charged ions) which makes them overall neutral.

Complete answer:
Let’s first understand how the chemical formulas for ionic compounds are written so that the resultant formula is neutral.
In an ionic compound, Cation ${{C}^{x+}}$and Anion ${{A}^{y-}}$are present. There should be neutrality and stability in the chemical formula ${{C}_{y}}{{A}_{x}}$.
The positive charge and the negative charge present neutralize each other which makes the compound neutral.
So, ions required to write the chemical formula are-
Cations:
Sodium- $N{{a}^{+}}$
Caesium- $C{{s}^{+}}$
Magnesium- $M{{g}^{2+}}$
Anions:
Sulphide- ${{S}^{2-}}$
Bromide- $B{{r}^{-}}$
Nitride- ${{N}^{3-}}$
The chemical formulas are:
Sodium sulphide- $N{{a}_{2}}S$
Caesium bromide- $CsBr$
Magnesium nitride- $M{{g}_{3}}{{N}_{2}}$
The chemical formulas must be ionically balanced, we should have prior knowledge of valency and charges.

Note:
Sodium sulphide- The inorganic chemical compound is a strongly alkaline solution. When it comes to the contact of moist air, it smells like rotten eggs. It is yellow when in the solid-state but colourless in the solution.
Caesium bromide- The ionic compound of caesium and bromine is a white solid that is dissolvable in water.
Magnesium nitride- The inorganic compound of magnesium and nitrogen which has three atoms of magnesium and two atoms of nitrogen. It is visible as a green-yellow powder at room temperature and pressure. It can be dissolved in acid and also slightly soluble in ethanol and ether.