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

Explanation

Ionisation energy of an atom is defined as the energy required to remove an electron from ground state energy level to its free state .
Ionisation energy of hydrogen is `E = + (me^(4))/( 8 in_(0)^(2) n^(2) h^(2)) = + 13.6eV`
If electron in hydrogen atom is replaced by a particle of mass 200 times that of electron (i.e., m = 200 m) but having the same charge then new ionisation energy of atom will be .
`E = +(m e^(4))/( 8 in_(0)^(2) n^(2) h^(2)) + ((200m)e^(4))/(8 in_(0)^(2) n^(2) h^(2)) = 200 E = 200 xx 13.6 eV = 2720 eV = 2.72 ke V`