Thomson's model could not explain these observations in thomson's model, electrons are spresd throughout the surface of the atom therefore, all the alpha particles should be deflected in a similar way, but this did not happen thomson's model had to be modified to explain why most alpha particles passed straight through the gold rutherford suggested that the atom must be mostly empty space he also suggested that there is a small, dense object at the centre of the atom this would explain why some of the alpha particles bounced straight back figure 1.13