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Matter

History of the atom and the atomic structure

1. JJ Thompson figured out that atoms weren't solid spheres, that contained Electrons

He came up with the plum pudding model

Negative atoms in that were spread through the positive atom like raisins on a plum pudding

2. Ernest Rutherford

Famous gold foil experiment

They fired positively charged alpha particles at an extremely thin gold sheet

They expected particles to pass right through, but more than they expected were deflected back

This meant that something positive was repelling the particles

Rutherford came up with a new model, the nuclear model, to explain all of this

In his model, most of the mass of an electron is concentrated in a tiny mass called the nucleus

It is surrounded by a cloud of electrons

Most of it is empty space