MCQ
Which one of the following elements forms compounds that are all coloured?
- AMagnesium.
- BAluminium.
- CIron.
- DChromium.
✓
Answer
- Chromium.
Explanation:
Most of the chromium compounds are coloured due to excitation of an electron from a lower energy d-orbital to higher energy d-orbital, the energy of excitation corresponds to the frequency of light absorbed. This frequency lies in a visible region. The colour observed corresponds to the complementary colour of light absorbed.
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