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Discuss the formation of coloured compounds by transition metals. |
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Answer» Solution :(1) The colour is due to the presence of one or more unpaired electrons in (N - 1) d-orbital. The transition metals have incompletely filled (n-1) d-orbitals. (2) The energy required to promote one or more electrons within the d-orbitals involving d-d TRANSITIONS is very low. (3) The energy CHANGES for d-d transitions lie in visible region ofelectromagnetic radiation. (4) Therefore transition METAL ions absorb the radiation in the visible region and APPEAR coloured. (5) Colour of ions of d-block elements depends on the number of unpaired electrons in (n – 1) d-orbital. The ions having equal number of unpaired electrons have similar colour. (6) The colour of metal ions is complementary to the colour of the radiation absorbed. |
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