Models of atoms

1808 - Dalton model

British chemist John Dalton published his," New System of Chemical Philosiphy", explaining that each element is made of small atoms and that different elements have atoms of different mass. Dalton imagined atoms as tiny, solid balls.

1911 - Rutherford model

British physicist Ernest Rutherford concluded that the atom is mostly empty space. Electrons orbit randomly around a small, positively charged nucleus.

1932 - Chadwick model

British physicist James Chadwick discovered the neutron, a particle having about the same mass as a proton but with no electical charge . The existence of the neutron explained why atoms were heavier than the total mass of their protons and electrons.

1897 - Thomson model

British scientist J.J.thomson suggested that an atom is a positively charged sphere with electrons embedded in it. His model could be described as looking like a muffin with berries scattered in it.

1913 - Bohr model

Danish physicist Niels Bohr determined that electrons arent randomly located around the nucleus. His models showed electrons moving in specific layers, or shells. He said that atoms absorb or give off energy when the electrons move from one shell to another.

1920s to present - Modern model

It shows the electrons as forming a negatively charged cloud around the nucleus . It is impossible to dtermine where an electron is at any given time.

1904 - Nagaoka model

Japanese physicist Hantaro Nagaokaproposed a model of the atom that had a large sphere in the center with a positive charge. His model showed the electrons revolving around this sphere like the planets around the sun.