Q. Copper exhibits only +2 oxidation state in its stable compounds. Why?
A) Copper is transition metal in +2 state.
B) +2 state compounds of copper are formed by exothermic reactions.
C) Electron configuration of copper in +2 state is $\lbrack Ar\rbrack 3d^{9}\ 4s^{0}$ .
D) Copper gives coloured compounds in +2 state.
Explanation
(b)
The Stability of ${Cu}^{2 +}$ (aq) rather than ${Cu}^{+}$ (aq) is due to much more negative $\mathrm{\Delta}_{hyd}H^{0}$ of ${Cu}^{2 +}$ (aq) than ${Cu}^{+}$ , which more than compensates for 2nd ionization enthalpy of Cu.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.