D And F Block Elements

more the charge on the atom, more is its stability.

electronic configuration of $\mathrm{Fe}^{2+}$ is $3 d^6$ while that of $\mathrm{Fe}^{3+}$ is $3 d^5$.

$\mathrm{Fe}^{2+}$ has a larger size than that of $\mathrm{Fe}^{3+}$.

$\mathrm{Fe}^{3+}$ ions are coloured.