After the electron was discovered by J.J. Thomson in 1897, people realised that atoms were made from even smaller particles than that they had previously thought. However, the atomic nucleus had not been discovered yet then the “plum pudding model” was suggests in 1904. during this model, the atom is formed from negative electrons that float during a “soup” of charge , very similar to plums during a pudding or raisins during a fruit cake (Figure 4.3). In 1906, Thomson was awarded the Nobel prize for his add this field. However, even with the Plum pudding Model, there was still no understanding of how these electrons within the atom were arranged.