https://padlet.com/400021574_2/ep00p0larkjdipy 😎 en-us 2021-09-16 18:56:28 UTC 2025-11-20 18:29:36 UTC hello@padlet.com https://padlet-uploads.storage.googleapis.com/1346460261/6b2681fcfa61819b5e6f36d1e8a8957c/unnamed__3_.jpg 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1748999962 claimed that matter was made of small hard particles he called "atoms" ]]> 2021-09-17 15:27:08 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1748999962 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749009540 Aristotle did not believe in the atomic theory and he taught so otherwise. He thought that all materials on Earth were not made of atoms, but of the four elements, Earth, Fire, Water, and Air. He believed all substances were made of small amounts of these four elements of matter.

]]> 2021-09-17 15:30:54 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749009540 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749020850 Dalton created the first chart of atomic weights. Seeking to expand on his theory, he readdressed the subject of atomic weight]]> 2021-09-17 15:35:18 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749020850 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749140841
Sir William Crookes studied the effects of sending an electric current through a gas in a sealed tube. The tube had electrodes at either end and a flow of electrically charged particles moved from one of electrodes. This electrode was called the cathode, and the particles were known as cathode rays.]]> 2021-09-17 16:23:57 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749140841 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749148728 Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.]]> 2021-09-17 16:27:41 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749148728 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749155263 Ernest Rutherford found that the atom is mostly empty space, with nearly all of its mass concentrated in a tiny central nucleus. The nucleus is positively charged and surrounded at a great distance by the negatively charged electrons.]]> 2021-09-17 16:30:41 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749155263 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749160207 Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons.]]> 2021-09-17 16:32:36 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749160207 400021574_2 https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749165397 Niels Bohr proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values]]> 2021-09-17 16:34:55 UTC https://padlet.com/400021574_2/ep00p0larkjdipy/wish/1749165397