Out of the following how many of them are coloured compounds.
`MnO_4^(ɵ),Cr_2O_7^(2-),CrO_4^(2-),Sc^(3+),Ti^(4+),Zn^(2+),Mn^(3+),Cu^(2+),Fe^(2+),Fe^(3+)`

Explanation

To determine how many of the given compounds are colored, we need to analyze each compound or ion based on the presence of unpaired electrons. Colored compounds typically arise from d-d transitions, which occur when there are unpaired electrons in the d-orbitals of transition metals.

Let's go through the list step by step:

1. **MnO₄⁻ (Permanganate ion)**:
- Manganese in MnO₄⁻ has an oxidation state of +7.
- Electronic configuration: Mn (Z=25) → [Ar] 3d⁵ 4s² → +7 means it has no d-electrons (3d⁰).
- **Conclusion**: Not colored.
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