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Democritus
Democritus was a Greek philosopher who put forward the idea that matter is made up of diminutive, indivisible, indestructible particles which he called "atomos". It is from the English word atom which means indivisible. Sorrowfully, he didn't have the necessary equipment to test and propose his ideas by using controlled experiments, so his ideas were eventually declined and rejected. -
John Dalton
John Dalton's theory's name is "Dalton's Atomic Theory". He uncovered the mystery of that all matter is made up of atoms. John Dalton also composed that all atoms of a given element are identical in mass and properties. Dalton discovered that compounds are formed by a combination of two or more different types of atoms. His theory also stated that a chemical reaction is a rearrangement of atoms. -
J. J. Thompson
J. J. Thompson was an English scientist that discovered the electron when he was experimenting with gas discharge tubes. He unearthed a new movement in the tube, he called it the movement in cathode rays. He also perceived to find out why electrons move from the negative end of the tube to the positive end. He realized that the opposite ends of the tube attract to each other. Thompson discerned that the rays were made of negatively charged particles which were electrons. -
Lord Ernest Rutherford
Ernest Rutherford conducted a well known experiment called the gold foil experiment. In his experiment, he utilized thin sheet of gold foil. Rutherford used unique and notable equipment to shoot alpha particles (which are positively charged) at the gold foil. He revealed that atoms are made of a small positive nucleus which repels or deflects positive alpha particles. Rutherford experiment displayed for us that atoms are mostly empty space because particles passed through the foil. -
Niels Bohr
Niels Bohr was a Danish physicist. He presented a model similar to the model of the solar system. His model's electrons go around the nucleus like how all the planets orbit around the sun. All of the electrons have their energy levels which is a precise distance from the nucleus. The 1st energy level holds 2, 2nd holds, 8, 3rd holds 18, and 4th holds 32 electrons. Bohr's main theory is that when electrons lose energy, they go down a level. When electrons gain energy, it goes down a level.
