As the below mind map graphically illustrates, the Thomson atomic model, the earliest theoretical description of the inner structure of atoms, was proposed about 1900 by William Thomson (Lord Kelvin) and strongly supported by Sir Joseph John Thomson, who had discovered (1897) the electron, a negatively charged part of every atom. As the mind map suggests, Thomson assumed that an electron is two thousand times lighter than a proton and believed that an atom is made up of thousands of electrons. In this atomic structure model, he considered atoms surrounded by a cloud having positive as well as negative charges. Use EdrawMax Online to create a model atom mind map similar to what is shown below.
