-online book
-Bohr Model
-Electron Cloud Model

At these sites you can see what parts make up the atomic models and the different types that have been made.
The atom is defined as the smallest part of an element that relates to the chemical properties of that element. The atom was first introduced in the early 400 B.C. Greek philosophers argued whether one could divide a substance into smaller pieces, or if eventually the smallest, indivisible particle would be reached. Around 450 B.C., the Greek philosopher Democritus claimed that all matter is made up of small, indivisible particles called atoms, which means indivisible. He also hypothesized that matter could not be divided into smaller and smaller particles forever. His ideas were met with much criticism, and it was not until the early 1800s that the early atomic theory took hold.
Democritus c460-371bc

J. J. Thomas 1856-1940
Lord Ernest Rutherford 1871-1937
Robert Millikan 1868-1953
Atomic models have their beginnings in the early atomic theory. The law of conservation of mass , the law of definite proportions, and the law of multiple proportions, provided models for the behavior of chemical reactions , but the laws could not be explained. In 1808, John Dalton (1766–1844) proposed his atomic theory, which served as an explanation for these phenomena. His theory consists of five postulates. The first postulate states that all matter is composed of atoms. Second, the atoms of a given element are all exactly the same in structure and properties. Third, atoms cannot be further divided, created, nor destroyed. Fourth, atoms of different elements combine to form compounds. Lastly, chemical reactions involve the combination, separation, and rearrangement of atoms. These five postulates not only explained the laws of conservation of mass definite proportions, and multiple proportions, but also served as the basis for the study and development of various atomic models.