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प्रश्न
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d orbital but reverse happens during the ionisation of the atom. Explain why?
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उत्तर
Electrons are filled to the n + l rule. If an orbital has lower n + l value, then the electron will enter that orbital.
For 3d, n + l = 3 + 2 = 5
4s, n + l = 4 + 0 = 4
So, the electron will first enter 4s and then 3d while filling. But, 4s electrons are held loose by the nucleus and are outside of 3d, so removing a 4s electron becomes easier than removing a 3d electron.
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संबंधित प्रश्न
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
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E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.
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The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain why?
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| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
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Reason (R): Because it has positive electrode potential.
Match List - I with List - II.
| List - I | List - II | ||
| (A) | [Fe(CN)6]3− | (i) | 5.92 BM |
| (B) | [Fe(H2O)6]3+ | (ii) | 0 BM |
| (C) | [Fe(CN)6]4− | (iii) | 4.90 BM |
| (D) | [Fe(H2O)6]2+ | (iv) | 1.73 BM |
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A pair of coloured ions is ______.
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Transition metals possess a great tendency to form complex compounds.
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Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
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