In any transition series, from left to right, the d-orbitals are progressively filled and their properties vary accordingly.
Q. In the second transition series, the largest number of oxidation states are shown by

Options

A. Tc
B. Ru
C. Rh
D. Pd

Explanation

To determine which element in the second transition series shows the largest number of oxidation states, we can analyze the electronic configurations and oxidation states of the given options: technetium (Tc), ruthenium (Ru), rhodium (Rh), and palladium (Pd).

### Step-by-Step Solution:

1. **Identify the Elements and Their Electronic Configurations:**
- Technetium (Tc): Atomic number 43, electronic configuration: [Kr] 4d^5 5s^2
- Ruthenium (Ru): Atomic number 44, electronic configuration: [Kr] 4d^7 5s^1
- Rhodium (Rh): Atomic number 45, electronic configuration: [Kr] 4d^8 5s^1
- Palladium (Pd): Atomic number 46, electronic configuration: [Kr] 4d^10 5s^0

2. **Determine Possible Oxidation States:**
- **Technetium (Tc):** Can exhibit oxidation states from +2 to +7.
- **Ruthenium (Ru):** Can exhibit oxidation states from +1 to +8.
- **Rhodium (Rh):** Can exhibit oxidation states from +1 to +9.
- **Palladium (Pd):** Typically shows oxidation states of +2 and +4, due to its fully filled d-orbitals.

3. **Compare the Number of Oxidation States:**
- Technetium: 6 oxidation states (from +2 to +7)
- Ruthenium: 8 oxidation states (from +1 to +8)
- Rhodium: 9 oxidation states (from +1 to +9)
- Palladium: 2 oxidation states (primarily +2 and +4)

4. **Conclusion:**
- Among the elements analyzed, Rhodium (Rh) has the largest number of oxidation states, which is 9.

### Final Answer:
The largest number of oxidation states in the second transition series is shown by **Rhodium (Rh)**.

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