Question

Why does the compound magnesium oxide have a melting point?

Answer 1

Hint: Magnesium oxide ( $MgO$ ), often known as magnesia, is a hygroscopic white solid mineral that occurs naturally as periclase and is a magnesium source. Magnesium oxide was previously referred to as magnesia alba.

Complete Step By Step Answer:
$MgO$ is an ionic solid that is non-molecular. The material is made up of an infinite number of magnesium and oxide ions linked by strong electrostatic bonds that run throughout the lattice.
Ionic compounds have a high melting point because they have an equal amount of positive and negative ions organised in a three-dimensional lattice. Ionic compounds dissolve in water to generate a solution in which ions can travel. This indicates that these solutions have the ability to conduct electricity.
The extremely strong forces of attraction between the oppositely charged ions hold the positive and negative ions generated during ionic bonding together. The ionic bonds between the charged particles form a large ion structure. Because the ions are tightly bound in this large structure, breaking all of the bonds takes a lot of energy.
Therefore, we can say that magnesium oxide has a high melting point.

Note:
 It is important to note that the melting point of ionic solids is also influenced by the ion ratio at which the solid dissociates. The smaller ion ratio suggests that the centre ion will surround a larger number of cations or anions, dividing the electrostatic force of attraction amongst oppositely charged ions. As a result, the melting point of the solid decreases.