Question

Ionization is the process by which an electron is removed from an atom. If the ionization energy of potassium is 418.8 kJ/mol, what is the maximum wavelength(in nm) of radiation that will ionize a potassium atom?

Answer 1

ionization energy of potassium = 418.8 kJ/mol

= 418.8 x 10^3 / 6.023 x 10^23

E = 6.95 x 10^-19 J

E = h C / $\lambda$

wave length $\lambda$   = h C / E

= 6.625 x 10^-34 x 3 x 10^8 /  6.95 x 10^-19

= 2.86 x 10^-7 m

= 286 nm

maximum wavelength(in nm) of radiation = 286 nm