∵ 1mol=6.023×1023 atoms KE of 1mol=6.023×104J or KE of 6.023×1023 atoms = 6.023×104J ∴ KE of 1 atom =
6.023×104
6.023×1023
=1.0×10−19J hvenergy=
hc
λ
=
6.626×10−34×3×108
600×10−9
=3.313×10−19J Now since Threshold energy = hv - KE =3.313×10−19−1.0×10−19=2.313×10−19J Hence minimum amount of energy required to remove an electron from the metal ion will be 2.313×10−19J.