Chemistry

Problem

Increasing order of stability of the +2 oxidation state of the ions ? a.

\text{Ca}^{2+} < \text{Ba}^{2+} < \text{Sr}^{2+}

\text{Pb}^{2+} < \text{Ge}^{2+} < \text{Sn}^{2+}

\text{Ge}^{2+} < \text{Sn}^{2+} < \text{Pb}^{2+}

\text{Cu}^{2+} < \text{Au}^{2+} < \text{Ag}^{2+}

Intuitive explanation

The stability of a +2 oxidation state depends on how easily an element loses electrons and how well it holds onto them once ionized. Elements in the same group show a trend: as you go down, the outer electrons are farther from the nucleus and more easily removed, but the resulting +2 ion becomes harder to oxidize further. The key is balancing ionization energy (how hard it is to form the ion) with the ion's resistance to further oxidation—which depends on electron configuration and nuclear charge.

Intuitive explanation

Browse the problem library