Question

The non-metal, which is hard, is

A.Sulfur
B.Chlorine
C.Graphite
D.Diamond

Answer 1

Hint: We have to know that non-metals are generally soft or hard but are brittle. We know that most of the non-metals exist as solids and gases at room temperature except bromine, which is liquid.

Complete step by step answer:
We also know that non-metals are brittle and cannot be rolled into sheets. They are poor conductors of heat and electricity. They also have a tendency to gain or share electrons with other species.
Now coming to the question, we have to identify non-metal that are hard.
We know that sulfur is a non-metal which belongs to the group 16 oxygen family and it exists as a solid.
We know that chlorine is a non-metal which belongs to the group 17 halogen family and it exists as a gas.
Graphite and diamond are allotropes of carbon (group 14).
Sulfur and graphite exist as non-metals that are soft in nature, whereas chlorine is a gas. Hence, option (A), (B) and (C) are incorrect.
Thus, we have identified Diamond as a non-metal that is hard in nature. Diamond has the highest value of hardness on Mohr’s scale.
We have to know that diamond is a complex network of carbon atoms, joined by strong covalent bonds that make up the hardness of it. It has a high melting point similar to that of silica.
In the structure of diamond, each atom of carbon is attached to four other atoms of carbon by strong covalent bonds. The atoms of carbon form a regular tetrahedral network.
Option (D) is correct.

Note:
We must know that the diamond does not conduct electricity, whereas graphite conducts electricity because in graphite there are delocalized electrons that move between layers, whereas in diamond the particles are not charged to move freely.