Question

When $C{r}^{4+}$ is oxidized to $C{r}^{6+}$, the $C{r}^{4+}$ ion:

• A. loses $2$ electrons
• B. loses $2$ protons
• C. gains $2$ electrons
• D. gains $2$ protons
• E. gains $1$ neutron

Answer 1

The correct option is A loses $2$ electrons

When $C{r}^{4+}$ is oxidized to $C{r}^{6+}$, the $C{r}^{4+}$ ion loses 2 electrons.
$C{r}^{4+}\to C{r}^{6+}+2e^{-}$
Oxidation is loss of electrons. The number of electrons lost is obtained from the difference in the oxidation number (or charge) before and after oxidation. The oxidation number of $Cr$ changes from +4 to +6.
Number of electrons lost $=6-4=2$