-
Democritus suggested that all objects or materials were made up of smaller things called 'atomos'. He theorized that each object/materials had different types of atomos and no matter how small they were cut up their properties would stay the same.
-
Aristotle didn't agree with Democritus. Instead, he theorized that materials didn't have separate particles but all contained one particle. He caused the idea of the atom and it's progress in science to slow down.
-
Lavoisier used a chemical reaction to come up with the Law of Conservation. This is the idea that matter cannot be created or destroyed, it must be conserved.
-
Came up with the Billiard Ball model of the atom. He suggested that everything was made up of indestructible particles that combine in different ways to make up elements we recognize. He theory also suggests that atoms of certain elements are different from those of other elements and in a chemical reaction atoms separate, combine, and rearrange in different ways.
-
Thomson furthered the plum pudding model. This model suggested that electrons floated around in a positively charged space, this made atoms electrically neutral. The pudding was considered the positive "goo" while the plums were the random electrons found in the "goo".
-
He began the beginning of nucleus atomic models. From a gold foil experiment he recognized that there was a middle of an atom, the nucleus. His model consists of a positively charged nucleus where negatively charged electrons would orbit around the nucleus like the planets around a sun.
-
Bohr's model is called the quantum or Bohr model. His model suggests that electrons don't spiral into the nucleus but orbit around it on different levels. This model also explains that the more energy an electron gives off the closer it will be to the nucleus, these orbits were sustained through electrostatic forces.
-
He helped discover the characteristics and activity of elementary particles.
