Atom models - after electrons were discovered in 1877, JJ Thompson created the plum pudding model. this showed a spherical area with a positive charge, and electrons dotted around within it, almost magnetized to it, and they couldn't get out from its field.Then, in 1905 this theory was tested, by suspending a thin piece of gold leaf within a vacuum, and then directing alpha particles at it, which is a highly positive form of nuclear radiation. It was thought all of these particles would pass through the foil, yet most passed through, some bounced of and some came straight back off the foil. This made him come to conclusions: there must be empty space within the atoms, allowing them to pass between the gold atoms, some of the positively charged atoms repelled the alpha atoms and finally, while small there was a chance for a small collision between their nuclei. The discovery of the nucleus, and subatomic particles followed afterwards. Niels Bohr then suggested the electrons orbited the nucleus.