Question

Why cu2+ is stable than Au 2+ where as both have d9 configuration

Answer 1

Answer on Question #80221 – Chemistry – Inorganic Chemistry

$\mathrm{Cu2+}$ is stable then $\mathrm{Au2+}$ , because despite the fact, that they have $d^9$ configuration, its electrons are on the different levels (Cu on 3, Au on 5), that is electronic configuration of $\mathrm{Cu2+}$ is $1s^22p^63s^23p^63d^9$ and $\mathrm{Au2+}$ is $1s^22p^63s^23p^63d^{10}4s^24p^64d^{10}5s^25p^65d^9$ . Charge of $\mathrm{Au^{2+}}$ higher than $\mathrm{Cu^{2+}}$ , but as they are ions, charge density of $\mathrm{Au^{2+}}$ lower than $\mathrm{Cu^{2+}}$ . And it is mean, that $\mathrm{Au^{2+}}$ worse stabilizes than $\mathrm{Cu^{2+}}$ .