Question

Magnesium metal is easily deformed by an applied force, whereas magnesium fluoride is shattered. Why do these two solids behave so differently?

Short answer

The reason behind the difference in the behaviour of the material framed from the same metal is the metal-metal bonding in the material. Mg-atom is a softer atom in behaviour.

Step-by-step solution

Intermolecular Forces

Intermolecular forces are the interaction which are formed by the attraction of the two having opposite charges(partial positive and partial negative charge). The opposite charge are formed by the presence of the electron-negative atom in the molecule. Due to the presence of an electron-negative atom, there is an induced partial positive charge is generated on the electron-positive charge (or less electron-negative charge) atom. There will be an attraction between the both oppositely charges to form a bond.

Metal-Metal bond can be defined as the bonding between the metal atoms formed by sharing or donating the electrons from the valence shell.

Explanation

Mg-atom is big in size as it is softer in nature. The bond formation between the Mg-Mg is also soft or weak which can be deformed by a small effort. But when the fluorine atom bond with Magnesium it becomes hard and when the force is applied, it shattered. F-atom is the most electronegative atom bonded with the metal atom to form Magnesium fluoride in which electrons are used to form a bond between the F-atom and Mg-atom. The bond is strong because of the interaction between the electropositive metal atom and electronegative F-atom.