Metal-metal bonding is more frequent in 4d or 5d series than in 3d series due to Tyndall effect. True/False

Answer

To determine whether the statement "Metal-metal bonding is more frequent in 4d or 5d series than in 3d series due to Tyndall effect" is true or false, we can analyze the concepts involved step by step.

### Step-by-Step Solution:

1. **Understanding Metal-Metal Bonding**:
- Metal-metal bonding refers to the interactions between metal atoms, which can lead to the formation of metallic bonds. The strength and frequency of these bonds can vary among different series of transition metals.

2. **Identifying the Transition Series**:
- The transition metals are divided into different series based on their electron configurations. The 3d series includes elements like Scandium (Sc) to Zinc (Zn), the 4d series includes Yttrium (Y) to Cadmium (Cd), and the 5d series includes Hafnium (Hf) to Copernicium (Cn).

3. **Enthalpy of Atomization**:
- The enthalpy of atomization is the energy required to separate one mole of a substance into its individual atoms in the gas phase. A higher enthalpy of atomization indicates stronger metal-metal bonding.
- The 4d and 5d transition metals generally have higher enthalpy of atomization compared to the 3d transition metals.

4. **Factors Affecting Enthalpy of Atomization**:
- The higher enthalpy of atomization in the 4d and 5d series can be attributed to:
- **Smaller Atomic Size**: The atomic size decreases across the periods, leading to stronger metallic bonding due to increased nuclear attraction.
- **Poor Shielding by f Orbitals**: The presence of f orbitals in the 4d and 5d series leads to poor shielding, which increases the effective nuclear charge experienced by the outer electrons, enhancing bonding.

5. **Tyndall Effect**:
- The Tyndall effect is the scattering of light by particles in a colloid or particles in a very fine suspension. It is not directly related to metal-metal bonding or the enthalpy of atomization.
- The statement incorrectly attributes the frequency of metal-metal bonding to the Tyndall effect, which is not the correct reasoning.

6. **Conclusion**:
- Since the statement claims that the frequency of metal-metal bonding in the 4d and 5d series is due to the Tyndall effect, and this is not true, we conclude that the statement is **False**.

### Final Answer:
**False**