Question

The ionization energy of $10$ times ionized sodium atom is

• A. $\frac{13.6}{11}eV$
• B. $\frac{13.6}{{(11)}^2}eV$
• C. $13.6\times {(11)}^{2}eV$
• D. $13.6eV$

Answer 1

Answer: (C)

The Bohr model of hydrogen atom can be extended to hydrogen like atoms. Energy of such an atom is given by
$E_n=-13.6\frac{Z^2}{n^2}$
Here, $Z=11$ for $Na$ atom; $10$ electrons are removed already, so it is $10$ limes ionised.
For the last electron to be removed, $n=1$
$\therefore$ $E_n=\frac{13.6(11{)}^2}{(1{)}^2}eV$
or $E_n=-13.6\times (11{)}^{2}eV$