In the formation of a compound AB, an atom of element A lost 2 electrons while an atom of element B gained 2 electrons. Predict two properties of AB.

1. Ionic compounds

Ionic compounds are formed between metals and non-metals in which there is a transfer of electrons from the metal to the non-metal.

When a metal and non-metal are brought close together, a transfer of electrons occurs from the metal to the non-metal. Both the atoms attain a stable electronic configuration. The cation formed due to the removal of an electron from the metal. The anion formed from the addition of an electron to non-metal is held together by an electrostatic force to form an ionic bond.

2. Compound AB

Compound AB is formed by transferring electrons from A to atom B. In this compound, atom A is the metal that loses 2 electrons to form a divalent cation. B is a non-metal that accepts A's electrons to form a divalent anion. The cation and anion from A and B are held together by electrostatic forces. Therefore, compound AB is an ionic compound.

${\mathrm{A}}^{2+}+{\mathrm{B}}^{2-}\to \mathrm{AB}$

The general properties of ionic compounds can be applied to the compound AB. Therefore, two properties of compound AB are:

1. It will have a high melting point. This is because ionic bonds are formed due to strong electrostatic attraction. Therefore, a high amount of energy is required to overcome these forces, and therefore, ionic compounds remain in the solid state.
2. Compound AB will be soluble in water. It will dissociate in solution to ${\mathrm{A}}^{2+}$ and ${\mathrm{B}}^{2-}$.