CHM 113 Lecture Notes - Mass Number, Robert Andrews Millikan, Ernest Rutherford
Document Summary
Elements are composed of various small particles called atoms. All atoms of the same element are identical to one another. Atoms of one element cannot be changed into atoms of a different element. Compounds are formed when atoms of more than one element combine with one another. Compounds always have the same relative number and kinds of atoms (law of. Atoms cannot be created nor destroyed in a chemical reaction (law of conservation of matter) J. j. thompson (1897) discovered cathode ray, a stream of electrons, by applying a charge to two electrons in an evacuated glass tube. Robert millikan (1909) used thompson"s data to calculate the charge and mass of an electron in his oil drop experiment. Henri berquierel, marie and piere currie, discovered atomic level disintegration called radioactivity. Ernest rutherford (1910) alpha particle scattering experiment, proved existence of dense positive nucleus in center of the atom, while also disproving plum pudding. Nucleus contains all of the protons and neutrons.
