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Aristotle
Did no think there was a limit to the number of times matter could be divided. -
John Dalton
Dalton proposed that all matter is made up of individual particles called atoms, which cannot be divided. For his experiment he used three solid sphere with different mass represented by each type of atom. -
Ernest Marsden
Ernest Marsden, bombarded gold atoms with massive, fast-moving alpha particles; when some of these particles were deflected backward, Rutherford concluded that the atom has a massive, charged nucleus. & his experiment that alpha particles from a radioactive source were occasionally deflected more than 90° when they hit a thin metal foil -
J.J. Thomson
He believed atoms are neutral, meaning it doesn't have an negative or postive charge. His experiment was he used a device, at the center of the device is a sealed glass tube from which most of air has been removed. Theres a metal disk at each end of the tube, wires connected the metal disks to a source of electric current. -
Hantaro Nagaoka
Nagaoka’s most notable work included the Saturnian model and his work on spectroscopy. How this contributed to our understanding of the atom: Nagaoka created an early, incorrect model of an atom using an analogy based on Saturn’s rings. -
Ernest Rutherford
Rutherford was a chemist and physicist who was known to be the father of nuclear physics.How this contributed to our understanding of the atom: Rutherford discovered the concept of the radioactive half life. He also differentiated and named alpha and beta radiation. Rutherford is credited for performing the first splitting of an atom. -
James Chadwick
Chadwick's own research focused on radioactivity.atomic number was less than the atomic mass, emperiment;, a helium atom has an atomic mass of 4, but an atomic number of 2. Since electrons have almost no mass, it seemed that something besides the protons in the nucleus were adding to the mass. -
Neils Bohr
How this contributed to our understanding of the atom: By expanding on Rutherford's earlier theory, Bohr published his theory which suggested that electrons travel in specific orbits around the nucleus, that outer orbits can hold more elctrons than the inner orbits and that these orbits determine the chemical properties of the atom. -
Louis de Broglie
He believed that electrons could behave as waves under some conditions, a finding that helped scientists understand that the atom didn't behave like the solar system because electrons do not move in regular orbits. -
Erwin Schrodinger
He contributed to the wave theory of matter and to other fundamentals of quantum mechanics. -
Democritus
Believed that all matter consisted of extremely small particles that could not be divided. Didnn't perform an experiment.
