Explain why Magnesium chloride has a high melting point.Please explain in details because this question has three marks.

To understand why this, and other ionic compounds have
such high melting points, you have to understand the difference between ionic and
covalent compounds.

In a covalent compound the bonding
between the elements takes place because there is a sharing of electrons between the
elements involved in the bonds.  Covalent compounds exist as discrete molecules with
little or no intermolecular attraction between the molecules and can move relatively
freely in relation to one another. Thus molecules such as methane (
CH4), CO2,
and larger molecules such as fats and oils are either liquids or gases at room
temperature or will readily melt with the addition of heat
energy.

Magnesium chloride is an example of an ionic
compound. That means it is composed of a positive magnesium ions which has lost two
electrons and two chlorine ions, each of which has gained one
electron.

Ionic compounds do not exist as individual,
discrete molecules but rather as a network if ions bonded to one another in a
crystalline structure.  Because the bonds between charged ions is very strong, and
because the ions are in a fixed, crystal network, it takes a large amount of energy to
break enough bonds to actually begin melting.