Question

Explain the position of actinoids in the periodic table.
What is the action of sulphur on lanthanoids? Calculate the magnetic moment of divalent ion in aqueous solution it its atomic number is 24.

Answer 1

Actinoids have a general electronic configuration  5f^d-14 6d^0-17s². 
They are placed at the bottom of periodic table. It follows actinium, Ac = (Z = 89).
i.e., It starts from the seventh period and 3rd group.
`2"Ln" +3"S" rightarrow "Ln"_2"S"_3`      (Ln is any lanthanoids)
                  X `rightarrow ` X²⁺ +2e^-
Electronic Configuration :1s² 2s² 2p⁶3s²3p⁶4s¹3d⁵ 
in +2 state : 1s² 2s² 2p⁶3s²3p⁶4s⁰3d⁴

Number of unpaired electron = 4

Magnetic moment `(mu) = sqrt(n"("n"+2)) = sqrt(4(4+2)) = sqrt(24) =4.89` B.M