When struck with a sharp blow ionic compounds tend to what while metallic substances which are what change sharpe?

Answer 1

Ionic compounds tend to shatter when struck with a hammer. This is due to the crystal structure formed by an ionic compound, which is basically repeating units of negatively and positively charged ions in some sort of geometric arrangement. When struck, ions of similar charge and pushed next to each other. These ions repel and the whole crystal will then cleave apart along the crystal pattern.

example: Left undisturbed NaCl crystal, right struck Na Cl :crys.tal breaks along crystal pattern

Na Cl Na Cl Na Cl

Cl Na Cl Na Cl Na Na Cl

Na Cl Na Cl Na Cl Cl Na

Cl Na Cl Na Cl Na Na Cl

Na Cl Cl Na

Metallic bonds are better pictured as an electron sea, where all the metal atoms that are participating are freely sharing electrons amongst each other. Because of this there are no localized charges to repel each other, making metallic bonds far less susceptible to shattering.

Answer 2

When struck with a sharp blow, ionic compounds tend to shatter into pieces due to their brittle nature, whereas metallic substances tend to deform and change shape due to their malleability and ductility.