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460
Democritus
Discovered in 460 BC. Everything is made up of individual particles called atoms, and atoms can't be created, destroyed, or divided. -
John Dalton
All matter is made up of atoms, and tiny particles that are industructable and cannot be divided. The atoms of the same element were exactly alike, and atoms of a specific element are different from those of another element. Atoms combine in simple whole number ratios, and atoms are seperated, combined, or rearranged in chemical reactions. -
J.J. Thomson
He discovered elements by demonstrating cathode rays that were negatively charged. Thomson realized that the accepted model of an atoms were filled with positive or negative cherged particles
. -
Ernest Rutherford
Discovered the nucleus, and he concluded that atoms consisted of a positively charged nucleus, and was surrounded by negative electrons, and has empty space. -
Neils Bohr
Bohr discovered that electrons orbits the nucleus, and as they change orbit they move up or down and release energy. -
Erwin Schrodinger
His theory states that hydrogen's atoms electrons move in a wave, the equation describes the likely hood of finding an electron in a certain postition. Where the electron cloud is most dense the probability of finding an electron is greater, vice versa. -
James Chadwick
Chadwick found that the composition of atoms also contained neutrons (which are located in the center of atoms, and weigh the same as protons)
