Question

Which of the following values corresponds to the value of energy required to remove the second electron from the ground state of helium atom?

• A. $-27.2eV$
• B. $-13.6eV$
• C. $-6.8eV$
• D. $-54.4eV$

Answer 1

The correct option is D $-54.4eV$

Removal of $2^{nd}$ electron from helium atom corresponds to the removal of an electron from $H{e}^{+}$ ion. The energy required is equal to the energy of the electron in that orbit.

Ionisation energy required to remove an electron $=13.6\frac{Z^2}{n^2}$

Given that $Z=2$ and $n=1$.

$E^{1}ofH{e}^{+}ion=-\frac{13.6}{1^2}\times 2^2$
$=-54.4eV$