Question

The ionization potential for second He electron is :

• A. $13.6eV$
• B. $27.2eV$
• C. $54.4eV$
• D. $100eV$

Answer 1

The correct option is A $13.6eV$

We know ionization potential for ae according to bohr

I.E$=13.6\frac{z^2}{n^2}eV$

$z=$atomic no.

$n=$ orbital no

for He $z=2$

and $n=1$ (in equation)

so, I.E$=13.6\times \frac{2^2}{1^2}eV$

$I.E=54.4$eV.