State true or false :
manganese metals exhibits the largest number of oxidation states in 3d series.

Explanation

To determine whether the statement "manganese metals exhibit the largest number of oxidation states in the 3d series" is true or false, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Element**: The question refers to manganese (Mn), which is a transition metal in the 3d series of the periodic table.

2. **Determine the Electron Configuration**: Manganese has an atomic number of 25. Its electron configuration is:
\[ \text{Mn: } [Ar] 3d^5 4s^2 \]

3. **Identify Possible Oxidation States**: Manganese can exhibit various oxidation states due to the involvement of both 3d and 4s electrons. The common oxidation states of manganese are:
- +2 (losing 2 electrons from 4s)
- +3 (losing 3 electrons, 2 from 4s and 1 from 3d)
- +4 (losing 4 electrons, 2 from 4s and 2 from 3d)
- +5 (losing 5 electrons, 2 from 4s and 3 from 3d)
- +6 (losing 6 electrons, 2 from 4s and 4 from 3d)
- +7 (losing all 5 from 3d and 2 from 4s)

4. **Count the Oxidation States**: From the above, manganese can exhibit oxidation states of +2, +3, +4, +5, +6, and +7. This gives a total of 6 different oxidation states.

5. **Compare with Other Transition Metals**: While other transition metals can exhibit multiple oxidation states, manganese is known to have the highest number of oxidation states in the 3d series.

6. **Conclusion**: Since manganese exhibits the largest number of oxidation states in the 3d series, the statement is **True**.

### Final Answer:
**True**