Which of the following does not apply to metallic bond ?

Options

A. Overlapping valence orbitals
B. Mobile valence electrons
C. Delocalised electrons
D. Highly directed bonds

Explanation

To determine which of the following statements does not apply to metallic bonds, we will analyze the properties of metallic bonds step by step.

### Step-by-Step Solution:

1. **Understanding Metallic Bonds**:
- Metallic bonds are formed between metal atoms. They involve the electrostatic attraction between positively charged metal ions and delocalized electrons.

2. **Property 1 - Non-Directional Nature**:
- Metallic bonds are non-directional. This means that the bonding does not have a specific orientation. The electrons are free to move in any direction, which is a characteristic of metallic bonding.

3. **Property 2 - Delocalized Electrons**:
- In metallic bonds, the electrons are delocalized. This means that the electrons are not associated with any specific atom but are free to move throughout the metal lattice. This property contributes to the conductivity of metals.

4. **Property 3 - Overlapping of Orbitals**:
- Metallic bonds involve overlapping of atomic orbitals. The presence of vacant orbitals in metal atoms allows for the formation of overlapping bonds, which helps in the delocalization of electrons.

5. **Property 4 - Mobility of Electrons**:
- The electrons in metallic bonds are mobile. This mobility is what allows metals to conduct electricity and heat effectively.

6. **Evaluating the Options**:
- Now, we will evaluate the options provided in the question:
- **A) Overlapping valence orbitals**: This applies to metallic bonds.
- **B) Mobile valence electrons**: This also applies to metallic bonds.
- **C) Delocalized electrons**: This is true for metallic bonds.
- **D) Highly directed bonds**: This does not apply to metallic bonds, as they are non-directional.

7. **Conclusion**:
- The option that does not apply to metallic bonds is **D) Highly directed bonds**.