Matching Pairs History of the Atomic TheoryOnline version atomic theory by Melissa Moreno 1 Cathode Ray Tube Set Up 2 Gold Foil Experiment Set Up 3 What instrument did J.J. Thomson use to discover the electron? 4 John Dalton proposed many postulates describing atoms. Which discovery disproved his idea that atoms cannot be divided into smaller particles? 5 What conclusion about the atom was Neils Bohr actually wrong about? 6 What conclusion did Rutherford make when most particles went through the gold foil but some were reflected back? 7 Why did J.J. Thomson conclude that electrons must be particles that are negatively charged? 8 How did Rutherford set up his famous experiment? 9 What important conclusion did Bohr’s model contribute to our understanding of atoms? 10 John Dalton proposed many postulates describing atoms. Which discovery disproved his idea that all atoms of an element are identical? They were particles because a magnet bent the cathode ray. They were negatively charged because they were attracted to a positive voltage. (Opposites attract) Rutherford shot alpha particles at a thin sheet of gold foil. The discovery of the neutron proved that atoms of the same element are NOT all identical The discovery of the electron proved that atoms are made of subatomic particles Electrons do NOT travel around the atom in fixed orbits Electrons are organized into different energy levels around the nucleus Most of the atom was empty space, and the mass was contained in a dense nucleus. J. J. Thomson used a cathode ray tube