Along the period `(rarr)` atomic`//`ionic radii and metallic character decreases while `IE`, `EN` , non-metallic character and oxidising power increases. Down the group `(darr)`, atomic`//`ionic radii, metallic character and reducing character increase while `IE` and `EN` decrease. However, `Delta_(eg)H^(ɵ)` becomes less negative down a group but more negative along a period.
If the ionic radii of `M^(o+)` and `X^(ɵ)` are about `135 p m`, then expected values of metallic radii of `M` and `X` should be respectively.

Options

A. `65` and `230 p m`
B. `230` and `60 p m`
C. `230` and `135 p m`
D. `135` and `135 p m`

Explanation

To solve the problem, we need to understand the relationship between ionic radii and metallic radii for the elements M and X. Given that the ionic radii of M⁺ and X⁻ are both approximately 135 picometers, we can derive the expected values of their metallic radii.

### Step-by-Step Solution:

1. **Understanding Ionic and Metallic Radii**:
- The ionic radius of a cation (M⁺) is smaller than its atomic radius (M), while the ionic radius of an anion (X⁻) is larger than its atomic radius (X).
- Therefore, if the ionic radius of M⁺ is 135 pm, then the atomic radius of M must be greater than 135 pm.
- Conversely, if the ionic radius of X⁻ is 135 pm, then the atomic radius of X must be less than 135 pm.

2. **Setting Up the Relationships**:
- For cation M⁺:
\[ \text{Ionic radius of M⁺} < \text{Atomic radius of M} \]
\[ 135 \text{ pm} < \text{Atomic radius of M} \]
- For anion X⁻:
\[ \text{Ionic radius of X⁻} > \text{Atomic radius of X} \]
\[ 135 \text{ pm} > \text{Atomic radius of X} \]

3. **Estimating the Values**:
- Since the ionic radius of M⁺ is 135 pm, we can estimate that the atomic radius of M could be around 230 pm (as cations are generally smaller than their parent atoms).
- Since the ionic radius of X⁻ is 135 pm, we can estimate that the atomic radius of X could be around 60 pm (as anions are generally larger than their parent atoms).

4. **Conclusion**:
- Therefore, the expected values of the metallic radii of M and X should be:
- Metallic radius of M: Greater than 135 pm, likely around 230 pm.
- Metallic radius of X: Less than 135 pm, likely around 60 pm.

5. **Final Answer**:
- The expected values of metallic radii of M and X are 230 pm and 60 pm, respectively.