∵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 Minimum amount of energy required to remove an electron from the metal ion (ie, Threshold energy) =hv−KE =3.313×10−19−1.0×10−19 =2.313×10−19J