Properties of Ionic Compounds

The element M forms the ionic oxide MO. Write the formula of the compounds formed when it reacts with chlorine and sulphur separately.

Element X is a metal with valency 2 and Y is a non-metal element with valency 3. Write the formula of ions of X and Y and also write the formula of the compound formed by X and Y.

Complete the table

Explain: Electrovalent compounds are usually hard crystals.

Choose from the following list as what matches the descriptions given below:

List: ${\mathrm{Ca}}^{2+}$, neon, ${\mathrm{H}}_2\mathrm{O},{\mathrm{C}}_2{\mathrm{H}}_2,{{\mathrm{NH}}_4}^{+},{\mathrm{NH}}_4\mathrm{Cl},{{\mathrm{NH}}_2}^{-},\mathrm{HCl}$

A cation iso-electronic with argon.

Sodium-ion is isoelectronic with neon.

The electro valency of calcium in calcium chloride is _____.