Question

The ionisation energy of hydrogen atom is $13.6$eV. What will be the ionisation energy of $H{e}^{+}$?

• A. $122.4$eV
• B. $54.4$eV
• C. $13.6$eV
• D. Zero

Answer 1

Answer: (B)

Ionisation energy of $H{e}^{+}=13.6\times Z^2$eV

$=13.6\times (2{)}^2$eV

$=13.6\times 4$eV $=$ $54.4$eV.