Thomson's model of the atom could not explain the result of the scattering experiment performed by Rutherford.
Atoms are stable
According to Thomson, an atom is a uniform positive sphere with electrons embedded in it, just like a plum pudding. This implies that when alpha particles are bombarded on the atoms, they should get deflected uniformly. However, in the scattering experiment, the deflection varied from 0∘ to 180∘ which couldn't be explained by Thomson's model.