Chemistry - PERIODIC TABLE Question with Solution | TestHub

An endothermic process absorbs energy. Removing an electron from a positively charged ion (ionization energy) requires energy input, making it endothermic. Increasing the positive charge of an ion always requires energy.

Option C: ${\mathrm{A}}^{+}\to {\mathrm{A}}^{3+}$ involves removing two electrons from ${\mathrm{A}}^{+}$, which is endothermic.

Option D: ${\mathrm{A}}^{+}\to {\mathrm{A}}^{2+}$ involves removing one electron from ${\mathrm{A}}^{+}$, which is endothermic.