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Ernest Rutherford (1871-1937) and his group in 1911 disproved the
Thomson’s atom model in a series of scatter experiments using alpha
particles and gold foils. He was surprised to discover that the largest
portion of the incident alpha particles was able to penetrate the foil having
Atoms: Rutherford
´
s Atom Model
been only slightly deflected. Only a small portion were scattered at large
angles.
According to these results, Rutherford suggested that the positive atomic
charge and almost all the atomic mass is concentrated in a very small
central body with a diameter of some
femtometers
(1 fm = 10
-15
m) instead of
being distributed over the whole volume of the atom with a diameter of
about 0.1nm. Originally Rutherford ignored the sign of the charge of the
nucleus, since as he pointed out, the angular distribution of the scattered
alpha particles is independent of the sign of the nuclear charge.