-
300
Democritus (BC)
Lived around 300b.c. He said thet the smallest part of matter is an atom. -
300
Aristotle (B.C.)
He lived around 300 B.C. and said that matter was composed of 4 elements known as water, earth, fire and wind. -
John Dalton
Said that each element are made of atoms that are all alike, Differant elements have atoms of differant mass and imagined atoms as tiny, solid spheres. -
J.J. Thomson
Atoms are positively charged spheres with electrons embedded in them. -
E. Rutherford
Electrons orbit around a small, positively charged nucleas, His model consisted of a positive nucleas surrounded by negative electrons -
Niels Bohr
Said that electrons move in specific energy levels around the positive nucleas, Bohrs model consisted of Electrons in energy levels -
Present Model of the Atom
The present model of the atom consists of an Electron cloud model, The position of an electron currently is impossible to predict, instead it forms a cloud of negative charge.
