The reason for the stability of $$G{d^{3 + }}\,ion$$ is
A.
$$4f$$ subshell - half filled.
B.
$$4f$$ subshell - completely filled.
C.
Possesses the general electronic configuration of noble gases.
D.
$$4f$$ subshell empty.
Answer :
$$4f$$ subshell - half filled.
Solution :
$$\eqalign{
& Gd\left( {Z = 64} \right) \Rightarrow 4{f^7}5{d^1}6{s^2} \cr
& G{d^{3 + }} = 4{f^7} \cr} $$
$$G{d^{3 + }}$$ is stable due to the presence of exactly half-filled $$4f$$ - subshell.
Releted MCQ Question on Inorganic Chemistry >> D and F Block Elements
Releted Question 1
When same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide, the ratio of volume of hydrogen evolved is