Why ionic crystals are hard and brittle ...

Why ionic crystals are hard and brittle ?

Text Solution

Verified by Experts

The ionic compounds are very hard and brittle. In ionic compounds the ions are rigidly held in a lattice because the positive and negative ions are strongly attracted to each and difficult to separate. But the brittleness of a compound is now easy to shift the position of atoms or ions in a lattice. If we apply a pressure on the ionic compounds the layers shifts slightly. The same charged ions in the lattice comes closer. A repulsive forces arises between same charged ions, due to this repulsions the lattice structure breaks down chemical bonding.

Topper's Solved these Questions

SAMPLE PAPER-4 (SOLVED)
FULL MARKS|Exercise PART - IV|11 Videos
SAMPLE PAPER-4 (SOLVED)
FULL MARKS|Exercise PART - II|9 Videos
SAMPLE PAPER 2 (SOLVED)
FULL MARKS|Exercise PART IV|5 Videos
SAMPLE PAPER-8
FULL MARKS|Exercise PART - IV|10 Videos

I. Anisotropy is the property which depends on the direction of measurement. II. Structural units of an ionic crystals are cations and anions. III. Amorphous solids are anisotropic in nature. IV. Crystalline solids have an orderly arrangements.

Only I

Only II

III & IV

I,II& IV

Assertion ( A) : Graphite is a good conductor of electricity. However diamond belongs to the category of insulators. Reason ( R ) : Graphite is soft in nature on the other hand diamond is very hard and brittle.

Both assertion and reason are true and reason is the correct explanation of assertion.

Both assertion and reason are true but reason is not the correct explanation of assertion.

Assertion is true but reason is false

Both assertion and reason are false.

The ionic crystals are not usually _____ .

Poor conductors

Opaque to visible radiation

Of high melting points

Very stable