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Dalton
John Dalton brought back the theory of atoms. The theory was all things are made of atoms just like Democritus had. He said all atoms of the same element are the same and atoms of other elements are different. Atoms join to create substances. His new theory was in chemical reactions atoms rearrange, combine, and separate. -
Sir William Crooks
Crooks invented a tube that had electrodes that were connected to a battery inside. It allowed electrons to travel through and he could see them. -
Dimitri Mendeleev
Mendeleev was a professor. He created the first periodic table of elements for his class. He organized the elements by their properties. The elements were organized by their atomic weight and valance. -
J.J Thomson
J.J Thomson expirimented with Crooks tube. He tried to hold a magnet to the side of it. The magnet bend the ray of electricity toward the positive side of the magnet. The outcome of the expiriment was: They ray has a negitive charge, because it's attracted to the positive magnet. -
Ernest Rutherford
He is one of Thomson's students. He discovered that atoms have a center called a nucleus. Necleus's are positive and are very dense. Rutherford figured this out by an expiriment where -
Niels Bohr
He discovered that electrons travel in paths around the center of the atom, the nucleus. The electrons move around the neucleus at differnet energy levels -
James Chadwick
Chadwick was the one who discovered the neutron. The neutral part of the atom. Neutrons make up the nucleus along with protons. -
Erwin Schrödinger
He expanded on Bohr. He invented the cloud model. For Hydrogen atoms you cant find where the electons are. Electrons has a cloud where you can expect it to be. -
Democritus 460-370 B.C
He was the first one to come up with the theory of atoms. They were called “atomos.” He thought that everything was made of small particle that are only one material. They always moved and joined to create things. -
Aristotle 350 B.C
Aristotle didn’t follow Democritus, because everyone thought he was crazy. Aristotle had his own ideas. He thought everything was made of 5 elements: Water, Earth, Fire, Wind, and Ether. Nobody thought he was crazy so this became the known fact.
