Atoms more complicated than hydrogen have more than one proton in their nucleus. Let Z stands for the number of protons in a nucleus. Also imagine that an atom loses all but one of its electrons so that it changes into a positively charged ion with just one electron. Bohr.s formula for the energy levels of the hydrogen atom can easily be changed to apply to such ions. It becomes `E_m = (-Z^2 e^4 m_e)/(8 epsi_0^2 h^2 n^2)`, where m= mass of electron , e= change of electron, n = orbit number.
The ionization potential of Het in ground state is

Options

A. `4.358 xx 10^(-18)` J/atom
B. `2.179 xx 10^(-18)` J/atom
C. `3.4864 xx 10^(-17)` J/atom
D. `8.716 xx 10^(-18)` J/atom

Answer

C

Explanation

IE = `-E_n = -((2.179 xx 10^(18)xx 4^2)/(1^2))`
`=3.486 xx 10^(-17) ` J/atom