We are constantly learning more and more about the atom. First, we thought that atoms were the basic building blocks of matter – in other words, that there was nothing smaller than an atom. Then, we discovered that atoms were actually made up of smaller particles called electrons, protons and neutrons (these particles were actually discovered in that order). Today, atoms are more complicated than ever, and particle accelerators such as the Large Hadron Collider at CERN are trying to find out more and more about the true nature of matter.
This video summaries many of the main developments in our understanding of the atom which were made up till 1932, and provides a useful historical overview to the remainder of this topic.
alpha particle, Bohr model, electromagnetic radiation, nuclear model, Geiger-Marsden experiment, atom, nucleus, proton, electron, neutron, mass, charge, plum pudding model, Rutherford model