Which of the following statement is incorrect with respect to metallic or electronic conductivity-

Options

A. Metallic conductivity depends on the structure of metal and its characteristics
B. Metallic conductivity depends on the number of electrons in the valence shell of atom of meta
C. The electrical conductivity of metal increases with increase in temperature
D. There is no change in the structure of metal during electrical conduction

Explanation

To determine which statement is incorrect with respect to metallic or electronic conductivity, we can analyze each statement based on our understanding of conductivity in metals.

### Step-by-Step Solution:

1. **Understanding Conductivity**:
- Conductivity (σ) is defined as the ability of a material to conduct electric current. It is the inverse of resistivity (ρ), which is a measure of how strongly a material opposes the flow of electric current. The relationship is given by the formula:
\[ \sigma = \frac{1}{\rho} \]
- Higher conductivity means lower resistance.

2. **Analyzing the Statements**:
- **Statement 1**: "Metallic conductivity depends on the structure of the metal and its characteristics."
- This statement is **correct**. The conductivity of metals is influenced by their atomic structure and the arrangement of atoms.

- **Statement 2**: "Metallic conductivity depends on the number of electrons in the valence shell or the atom of the metal."
- This statement is also **correct**. The number of free electrons available for conduction directly affects the metallic conductivity.

- **Statement 3**: "Electrical conductivity of metal increases with an increase in temperature."
- This statement is **incorrect**. In metals, as temperature increases, the resistance typically increases due to increased lattice vibrations, which leads to decreased conductivity.

- **Statement 4**: "There is no change in the structure of the metal during electrical conduction."
- This statement is **incorrect**. During electrical conduction, the structure of the metal can change due to factors like heating or electron movement, which can affect the metal's properties.

3. **Conclusion**:
- The incorrect statement among the options provided is **Statement 3**: "Electrical conductivity of metal increases with an increase in temperature."

### Final Answer:
The incorrect statement with respect to metallic or electronic conductivity is: **"Electrical conductivity of metal increases with an increase in temperature."**