Question

Consider the following statements:
I: In diamond, each carbon atom is linked tetrahedrally to four other carbon atoms by $s{p}^3$ bonds.
II: Graphite has planar hexagonal layers of carbon atoms held together by weak van der Waal's forces.
III: Silicon exists only in diamond structure due to its tendency to form $p\pi -p\pi$ bonds to itself.

In this:

• A. only I and II are correct.
• B. only I is correct
• C. only II and III are correct.
• D. all the above are correct statement

Answer 1

Answer: (A)

only I and II are correct.

Diamond: $C$ is $s{p}^3$ hybridised. C is tetrahedrally linked to $4$ neighbouring $C$ atoms through $4$ strong bonds between them as $s{p}_3$ bonds. It extends in $3-D$ and give rise to $3-D$ structure. It is very rigid. It is used as gems in making abrasive. Since all the electrons firmly held so it do not conduct electricity as no 'free electron' is present.

Graphite: $C$ is $s{p}^2$ hybridised. Each $C$ is linked to $3$ other creations forming hexagonal rings. So, it has $2-D$ sheet-like structure. The various sheets are held by Van der Waal's force of attraction. The layers can slip over the other.

Silicon: It exists in different kinds of structures based on its bonding atoms.