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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
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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.
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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.
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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.
