Atomic Theory Polka Dalton, Thomson, Rutherford and Bohr. Schrödinger and Heisenberg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.
Dalton did experiments and said, “I think it’s clear, atoms are tiny indestructible spheres.”
Thomson worked with cathode rays and said, “I disagree. A plum-pudding model makes much more sense to me.”
A new chapter in atomic theory started to unfold when Rutherford played around with atoms made of gold. When a few of his alpha particles came bounding back, he hypothesized a nucleus had knocked them off the track.
Dalton, Thomson, Rutherford and Bohr. Schrödinger and Heisenberg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.
Bohr saw spectral lines for hydrogen and said, “It seems to me.. Electrons move in orbits with specific energies.”
Heisenberg said, “Forget it, there’s no way to know the orbit or a path, where the electron’s gonna go.”
Schrödinger used lots and lots of fancy mathematics, and made a model of the atom based on quantum mechanics. It has orbitals and those are based on probability. The atom is a fuzzy blob of pure uncertainty.
Dalton, Thomson, Rutherford and Bohr. Schroedinger and Heisenburg, and many, many more. Used their brains to venture in the realm of inner space and found the world of the atom was a weird and wondrous place.
Read 4.2 – 4.3 in a 6 inch voice Fill out the study guide as you read in complete sentences. Use your own words! It will help you to remember more.
JJ Thomson Found electron Used cathode ray tube “Plum Pudding” or “Chocolate Chip Cookies” model
Robert Millikan Determined the electrical charge of electron “Oil Drop Experiment” Still plum pudding model
Eugen Goldstein Found the proton Reverse cathode ray tube Still plum pudding model
Ernest Rutherford Found nucleus Gold foil experiment Atom is mostly empty space – first nuclear model
James Chadwick Found neutron Shot alpha particles at Be nucleus Nucleus is made of two particles Positive protons Neutral neutrons
Niels Bohr Planetary model Proposed electrons have a set amount of energy putting them in different energy levels, or orbits around the nucleus. Electrons can change energy levels; higher energy levels are further from the nucleus.
Heisenberg’s uncertainty principle Heisenberg’s uncertainty principle: cannot know exactly both the velocity and position of electron at the same time. Like trying to catch a helium balloon in the dark.
Schrödinger Electron cloud gives a 90% probability of finding the electron within the darkly shaded area. Electrons move like moths around a light – unpredictable.