Models of the atom

There were many beliefs about the correct model of the atom, from scientist to scientist, more evidence was discovered about the models of the atom.

The first scientist known to 'discover' the model of the atom was Democritus during the year -400 B.C. His mentor, Leucippus, originally came up with the atomic theory, but it was then adopted by Democritus. The atomic theory stated that “The universe is composed of two elements: the atoms and the void in which they exist and move.” According to Democritus atoms were miniscule quantities of matter. There are more statements that the atomic theory states:"1.All matter consists of invisible particles called atoms.""2. Atoms are indestructible.""3. Atoms are solid but invisible.""4. Atoms are homogenous.""5. Atoms differ in size, shape, mass, position, and arrangement.""->Solids are made of small, pointy atoms.""->Liquids are made of large, round atoms.""->Oils are made of very fine, small atoms that can easily slip past each other."As humorous as these statements are, Democritus and Leucippus did manage to identify that atoms do exist, to identify such a big discovery in -400 B.C, is truly incredible.

Democritus' model was believed to be the correct model of the atom for quite a long period of time. However, In 1830, John Dalton identified a new theory for the models of atoms (well it isn't entirely new). "1) All matter is made of atoms. Atoms are indivisible and indestructible.""2) All atoms of a given element are identical in mass and properties""3) Compounds are formed by a combination of two or more different kinds of atoms.""4) A chemical reaction is a rearrangement of atoms."Dalton's theory isn't entirely correct, but the essence of Dalton's theory remains valid.

So far, two theories were available for people to believe, however, In 1904, Thomson's plum pudding model raised a few heads. In Thomson's model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged “plums” surrounded by positively charged “pudding”. The 1904 Thomson model was disproved by Hans Geiger's and Ernest Marsden's 1909 gold foil experiment.

The Geiger–Marsden experiment (also called the Rutherford gold foil experiment) were a series of experiments by which scientists discovered that every atom contains a nucleus where all of its positive charge and most of its mass are concentrated. This led to Ernest Rutherford's model of the atom, which plays a huge part in our modern scientific phenomenon. Rutherford's model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.

Ernest Rutherford set to improve on his own model, believing that he could find the correct model of the atom. With help from Niels Bohr in 1913, the Bohr model depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar to structure of the Solar System, but with attraction provided by electrostatic forces rather than gravity.