Copper exhibits only +2 oxidation state in its stable compounds. Why?

Options

A. Coppper is a transition metal in +2 state
B. `+` 2 state compounds of copper are formed by exothermic reactions
C. Electron i.e. configuration of copper in '+'2 state is `[Ar]3d^(9) 4s^(0)`
D. copper gives coloured compounds in '+' 2 state

Answer

B

Explanation

The stability of `Cu^(2+)`(aq) rather then `Cu^(+)`,(aq) is due to much more negative `Delta_("hyd")H^(@) " of " Cu^(2+)`(aq) than `Cu^(+)`, which compensates for second ionisation enthalpy of Cu.