Proposed the idea of indivisible particles called atomos
Law of Conservation of Matter, Mass of Reactants = Mass of Products
Law of Definite Proportions, The proportion by mass of the elements in a given compound is always the same.
System of symbols for elements
Made the first vacuum tube.
Sir William Crookes
Used a vacuum tube to discover what are now called cathode rays
Discovered the existence of charges particles
Discovered the existence of X-Rays
Discovered the existence of radioactivity
Discovered cathode rays to be electrons. Measured charge to mass ratio of electrons. Plan-pudding model of atom. Electrons implanted in sphere of solid charge. Atom is neutral. Mass of atom is evenly distributed.
Famous oil drop experiment in which he measured the charge of an electron to be 1.6×10^(-19) coulombs. Used the charge to mass ratio found by Thomson to find the mass of the electron to be 9.1×10^(-28)g.
Gold Foil Experiment in which he discovered the nucleus of the Atom. He attributed the deflection of alpha particles to the concentration of positive charge and mass at the center of the atom. Planetary Atomic Model. Positively Charges nucleus containing the mass of the atom with electrons orbiting the nucleus at high speeds. The Electrons are equal in number to the positive charge of the nucleus.
Developed atomic number concept
Discovered the existence of isotopes
Discovered the electrons. It was named and predicted by Rutherford.
Quantum theory of light-Light exists in small energy packets called quanta or photons.
Particles(like electrons) can have a wave-like character
George P. Thomson
Confirmed DeBroglie’s ideas experimentally. He found that when directing a stream of electrons at a diffraction grating the same results were obtained as were obtained with light.
Heisenburg Uncertainty Principle. It is impossible to know both the location and velocity of an electron at the same time