John Dalton revolutionized science in 1803 when he hypothesized that atoms of different chemical elements, such as hydrogen and oxygen, had different characteristic masses. J.J. Thomson discovered the first subatomic particle -the electron - in 1897. Ernest Rutherford revealed the presence of a dense central nucleus in atoms in 1911. In 1913, Niels Bohr proposed that electrons in atoms are confined to certain allowed (restricted) orbits. In 1924, Prince Louis Victor de Broglie produced a better description of atoms, which included the wavelike property of the quickly orbiting electrons. By 1928, Edwin Schrodinger, Wolfgang Pauli and Max Born had described the atom using quantum mechanical principles.