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John Dalton
The atom is an indestructible sphere that is the same all the way through. It was at this time that John Dalton, an English chemist, meteorologist and physicist, began a series of experiments which would culminate in him proposing the theory of atomic compositions -
JJ Thomson
The atom is a sphere of positively charged material with tiny negatively charged electrons inside it, like currants in a plum pudding.Thomson discovered the electron, a negatively charged particle more than two thousand times lighter than a hydrogen atom. -
Ernest Rutherford // Niels Bohr
Thomson discovered the electron, a negatively charged particle more than two thousand times lighter than a hydrogen atom. Scientists guessed that since electrons are extremely small, whatever this positive something was, it must be make up most of the mass of atoms, and be much larger. -
Erwin Schroedinger
The nucleus in the centre contains protons and neutrons. The electrons trace out very complex regions that look like different-shaped ‘clouds’ as they spin around the nucleus. Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom.
