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Democritus
Democritus was a Greek philosopher who proposed the idea that matter is made up of tiny, indivisible, indestructible particles that he called atomos, from which the English word meaning atom (meaning indivisible). The Democritus's atom is tiny, indivisible, and indestructible particles. Democritus idea was rejected. It was rejected because he did not have the necessary equipment to test his ideas.
https://www.youtube.com/watch?v=TgWn91ap99A -
Lord Ernest Rutherford
The charge of an alpha particle is positive. It's called the gold foil experiment because he used a thin sheet of gold foil. He knew that an atom was mostly empty space when particles would pass straight through the foil as if it is not even there. When the alpha particles hit the gold foil some went right pass the foil and some went straight pass the foil. He knew that the nucleus was positively charged when it repealed.
https://www.youtube.com/watch?v=Q9zFWIfUHvc -
J. J. Thompson
J. J. Thompson was an English scientist. He discovered the electron when he was experimenting with gas discharge tubes. The charge of an electron is a negative charge. Cathode rays are made up of electrons. Electrons move from the negative end of the tube to the positive end of the tube because and electron carries a negative charge and in electricity opposites attract. Thompson was working with gas discharge tubes when he discovered cathode rays.
https://www.youtube.com/watch?v=hsLf_AJGsbw -
Niels Bohr
Bohr was a Danish chemist. Bohr's model could be a planetary model of an atom because the electrons go around the nucleus like planets orbit the sun. Electrons in the same atom differ because they all have different energy levels.The 4 ring can hold up to 32 electrons. An electron would have to absorb energy to jump from the 2nd ring to the third.For an electron to fall from the 3rd ring to the 2 ring it has to release energy.
http://www.teachertube.com/video/bohr039s-model-of-the-atom-213936 -
John Dalton
John Dalton is an English chemist. Dalton's ideas form the atomic theory of matter. The name of John Dalton's theory is called Dalton's atomic theory, Dalton said all elements are made of atoms. Dalton also said that compounds are two or more different elements. He also said that an atom of hydrogen and an atom of carbon is called hydrogen bonds.
https://www.youtube.com/watch?v=HB2I2IjOmRY
