https://padlet.com/athanurkholis/x41xqfofj2m39g1d en-us 2022-10-14 03:50:48 UTC 2025-10-17 15:57:38 UTC hello@padlet.com athanurkholis https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339792590 In 1803, the theory became the first full attempt at describing matter. First, all matter is made up of atoms. They are indivisible and indestructible. Second, elements are made up of identical atoms. The atoms of different elements contain different masses. Third, atoms of elements combine in a whole number ratio to form a compound.]]> 2022-10-14 03:55:10 UTC https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339792590 athanurkholis https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339797511 J. J. Thomson placed two plates on opposite sides around the cathode ray. The ray was drawn onto the positively charged plate, this is the same with two magnets around it. The cathode ray must be made out of negatively-charged particles. These particles have the same mass in each element: Around 1/2000 the mass of an H atom. These negatively-charged particles are called "electrons" and are present in all elements.]]> 2022-10-14 04:01:08 UTC https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339797511 athanurkholis https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339798270 Ernest Rutherford shot a thin gold foil with a thin beam of alpha particles. Alpha particles are He nuclei and are given off in various processes of radioactive decay. When the beam hit the gold foil, some parts of the beam scattered instead of passing straight through it. In this model, atoms are mostly made up of empty space. Positively-charged particles are bundled up in a tiny volume of the atom which contains lots of mass.]]> 2022-10-14 04:02:09 UTC https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339798270 athanurkholis https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339798973 Niels Bohr's theory explained that electrons move in a fixed orbit. Each orbit (shell) has a fixed energy level with the furthest orbit being the valence shell. This is similar to the rings of Saturn, or more accurately the planets orbiting around the Sun. This model doesn't work with systems with more than one electron.]]> 2022-10-14 04:03:13 UTC https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339798973 athanurkholis https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339800435 Erwin Schrodinger's theory treats electrons as matter waves. Matter behaves strangely at the subatomic level like when an electron behaves like a particle and a wave. Electrons have an intrinsic property called "spin", there are two possible "spins" which are "spin-up" and "spin-down". In an orbit, two electrons must have spins that are opposite to each other.]]> 2022-10-14 04:05:08 UTC https://padlet.com/athanurkholis/x41xqfofj2m39g1d/wish/2339800435