Which one of the following has strongest metallic bonding ?

Options

A. Fe
B. Sc
C. V
D. Cr

Answer

To determine which of the given metals has the strongest metallic bonding, we need to analyze the number of unpaired electrons in the d-orbitals of each metal. The strength of metallic bonding is closely related to the number of unpaired electrons, as more unpaired electrons lead to stronger electrostatic interactions between the positively charged metal ions and the delocalized electrons.

### Step-by-Step Solution:

1. **Identify the Metals and Their Electron Configurations**:
- **Iron (Fe)**: Atomic number 26; Electron configuration: [Ar] 3d^6 4s^2
- **Scandium (Sc)**: Atomic number 21; Electron configuration: [Ar] 3d^1 4s^2
- **Vanadium (V)**: Atomic number 23; Electron configuration: [Ar] 3d^3 4s^2
- **Chromium (Cr)**: Atomic number 24; Electron configuration: [Ar] 3d^5 4s^1

2. **Count the Unpaired Electrons**:
- **Iron (Fe)**: In the 3d subshell, there are 4 unpaired electrons (3d^6 configuration leads to 4 unpaired).
- **Scandium (Sc)**: There is 1 unpaired electron (3d^1).
- **Vanadium (V)**: There are 3 unpaired electrons (3d^3).
- **Chromium (Cr)**: There are 6 unpaired electrons (3d^5 4s^1).

3. **Analyze the Strength of Metallic Bonding**:
- The strength of metallic bonds increases with the number of unpaired electrons.
- **Iron (Fe)** has 4 unpaired electrons.
- **Scandium (Sc)** has 1 unpaired electron.
- **Vanadium (V)** has 3 unpaired electrons.
- **Chromium (Cr)** has 6 unpaired electrons, which is the highest among the four metals.

4. **Conclusion**:
- Since chromium has the highest number of unpaired electrons (6), it will have the strongest metallic bonding among the given options.

### Final Answer:
The metal with the strongest metallic bonding is **Chromium (Cr)**.