Indian Forest Service (Mains), Chemistry optional · 2016 · Paper I

Q6(b)(i). General electronic configurations of the 4f and 5f elements

5 marks
Topic: General chemistry of 'f' block elements
Question only

Question

Write the general expressions for the filling of electrons in 4f and 5f block elements.

Model answer

The 2016 solution on this site answers questions 1, 2, 4, 5 and 7, the ones picked in its time plan. This part is not answered on the site yet. New answers are announced on Telegram.

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Topic notes: lanthanides and actinides (lanthanide contraction, magnetic moments, separation), with every Civil Services, IFoS and Geo-Scientist PYQ →

All parts of Question 6

6(a)(i) Crystal field stabilisation energy and the factors that fix it10 marks
6(a)(ii) CFSE and magnetic moments of FeCl₃.6H₂O and K₄[Fe(CN)₆]10 marks
6(b)(i) General electronic configurations of the 4f and 5f elements5 marks
6(b)(ii) Lanthanide contraction; effect on 4f and 5d chemistry5 marks
6(c)(i) IUPAC names of two complexes5 marks
6(c)(ii) Ce³⁺ colourless, Ti³⁺ purple5 marks