-
400
Democritus (about 400 B.C.)
There were infite numbers of atoms in the world. He knew the atoms were invisible and indivisible particles of matter. Also everything is made up of atoms and there always in motion. He based his theory on his observation and curiosity. The atom was the smallest particles of matter. He sometimes called the atoms "uncutable" or "atomos". -
Dalton(1808)
He was able to build on Democcritus idea of atoms. He discovered that the atoms are indivisible. It explained why a weight of one substance always combines with a fixed weight of another substance to become a compound. He discovered his method by experiencing it. -
Rutherford
He discovered the atoms consisted of subatomicc particles named protons and electrons. He tested Thomson's guest by devising his "gold foil". Also he tested his first experiment with a film of gold atoms and thats how he made his discovery. One method included particles on a thin layer of zinc sulfide. -
Thomson
The atoms is known to contain other particles. He found rays made up of electrons. His hypotheses were followed by crucial experimental and theoretical by others. Also he had investigated a long-standing puzzle known as "cathode rays." The particles were called "corpuscles". -
Bohr
He proposed a theory for the hydrogen atom. His theory of atomic structure in which the hydrogen atom is assumed to consist of a proton. He said, "The atom will be completely stable in the state with the smallest orbit, since there is no orbit of lower energy into which the electron can jump."
