Question

The order of ionisation potential between ${He}^{+}$ ion and $H-atom$(both species are in gaseous state) is:

• A. $I.P.\left({He}^{+}\right)=I.P.\left(H\right)$
• B. $I.P.\left(H{e}^{+}\right)<I.P.\left(H\right)$
• C. $I.P.\left({He}^{+}\right)>I.P.\left(H\right)$
• D. cannot be determined

Answer 1

Answer: (C)

$I.P.\left({He}^{+}\right)>I.P.\left(H\right)$

${He}^{+}$ and $H$ atom have only one electron, we know for isoelectronic species the species with highest nuclear charge have high ionization energy than other.

$I.P.\left({He}^{+}\right)>I.P\left(H\right)$