Question

Which of the following statement is incorrect based on covalent bond characteristics?

• A. Covalent bonds are non-directional in nature
• B. Diamond has a very high hardness due to strong covalent bonding
• C. Silicon and germanium form covalently bonded crystal structures
• D. Covalent bonding involves shared electrons between atoms

Hint:

Directional bonding is responsible for fixed crystal structures in covalent solids.

Answer 1

The Correct Option is A

Concept: Covalent bonding arises due to the sharing of electrons between atoms through orbital overlap. The directionality of bonding depends on the geometry of orbitals involved (sp, sp$^2$, sp$^3$ hybridization). This makes covalent bonds highly directional in nature.

Step 1: Nature of covalent bonds.
Covalent bonds:
• formed by sharing of electron pairs
• depend on directional orbital overlap
• lead to fixed bond angles Hence statement (A) is incorrect because covalent bonds are strongly directional.

Step 2: Diamond structure.
Diamond has:
• sp$^3$ hybridized carbon atoms
• strong 3D covalent network
• very high hardness due to strong directional bonding Thus (B) is correct.

Step 3: Silicon and germanium structure.
Both Si and Ge:
• form diamond cubic structure
• exhibit covalent bonding Thus (C) is correct.

Step 4: Definition of covalent bonding.
Covalent bonding is: \[ \text{sharing of electrons between atoms} \] Thus (D) is correct. Final Answer: \[ \boxed{\text{Covalent bonds are non-directional in nature (incorrect statement)}} \]