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450
450 BCE: Democritus
Democritus formed the hypothesis that everything was made up of Atoms and basically all of our information that we have this day is the same as his, but the only wrong thing that he had was his interpretation of the look of the Atom. The earliest views on the shape of the atom depended on what the materials were. Salt atoms (because of the taste) were thought to be sharp and pointed, while water atoms were thought to be smooth and slippery. -
1803: John Dalton
John Dalton had many handicaps, but that didn't stop him from making the next major discoveries, he was also the first to make a table of relative Atomic weights, but his four main discoveries were that:
1.) All matter is made of tiny particles
2.) Atoms are indestructible and also unchangeable
3.) The characterization of elements is based on the mass of the atom
4.) When elements react, their atoms combine in simple whole number ratios. -
1897- JJ Thomson
JJ Thomson proposed a great theory, which was that there are "subatomic particles" 1000 times lighter than the Atom, now known as Electrons. He made this discovery through his exploration on the properties of the cathode rays. -
1910: Earnest Rutherford
Rutherford is considered the father of nuclear physics, it also could be said that he invented the language to describe the theoretical concepts of the atom. He also has particles characterized by him, which are the Alpha, Beta, and Proton particles. He overturned Thomson's atom model a year after his discovery with his well-known gold foil experiment in which he demonstrated that the atom has a tiny but massive (in small terms) Nucleus. -
1913: Neils Bhor
Bohr's model is most famously known as the "Planetary Model", was the first accurate Atomic Model. In his model, Neutrons and Protons live in the nucleus, and the Electrons orbit the nucleus like planets orbiting the sun, but the orbits are not confined to a specific plane. -
1926: Irwin Schrödinger
Schrödinger stated that Electrons were arranged in orbitals which were systematically distributed within the Electron Cloud rather than being distributed within a configured shell with a configured energy level. His model shows the orbital around the nucleus in constant motion, equidistant from each other and at different angles; this was made to represent the function of waves. -
1932: James Chadwick
Chadwick discovered a previously unknown particle in the nucleus. Chadwick discovered the Neutron; he came to this conclusion because of its lack of electrical charge.
