Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Worksheet 3.1 People Who Helped Develop the Modern Model of the Atom Empedocles: Greek philosopher, thought all matter was made of the 4 elements: earth, wind, fire, water Democritus: Greek philosopher, thought all matter was divisible into tiny, indivisible particles he called “atoms”. Purely speculative. John Dalton: Scientist, first to show scientifically the idea of atoms, and came up with the Law of Definite Composition and the Law of Multiple Proportions. J.J. Thomson: discovered the electron, discovered that the atom was NOT the smallest particle, and developed the “plum pudding” model of the atom, where the positive and negative charges were evenly distributed. Ernest Rutherford: shot alpha particles through thin gold foil to show that the mass of the atom was concentrated in the middle, or nucleus, which is where the proton are. Niels Bohr: studied the line spectrum of elements to find that the electrons exist in orbits, where only certain, specific energy levels are possible (the electron’s energy levels are ‘quantized’). His model of the atom has electrons traveling around the nucleus in orbits, similar to planets around the sun. Erwin Schrödinger: based atomic model on statistics and probability. Replaced Bohr’s orbits with “orbitals” or “clouds” of various shapes (s, p, d, f). James Chadwick: found the neutron.