Question

Define ionization energy.
How would the ionization energy change, when an electron in hydrogen atom is replaced by a particle of mass 200 times that of the electron but having the same charge ?

Answer 1

Ionization energy is defined as the amount of energy needed to remove the valence electron of an isolated gaseous atom.
The ionization energy of hydrogen atom is
$E_H\propto m_e...\left(i\right)$

When mass of electron is replaced by a particle having mass =$200m_e$,then
$E_H^{\prime }\propto 200m_e...\left(ii\right)$

From (i) and (ii), we have
$E_H^{\prime }=200E_H=200\times (-13.6)=-2720eV$
$(\because E_H=-13.6eV)$