The Timeline of Atoms :<3: (1897 - J.J. Thomson (He showed atoms as…
The Timeline of Atoms :<3:
440 BCE - Democritus
He called the particles "atomos", which meant uncuttable.
This rebelled against Aristotle's idea that everything was made from four elements; fire, water, earth, and wind
Democritus first proposed that everything was made from tiny particles.
1897 - J.J. Thomson
He showed atoms as spheres packed with positive matter, with electrons surrounding the atom.
He made a model of an atom that what is known today as the "plum-pudding" model
Thomson won a Nobel Prize for his discovery, but his model was soon rebutted by some of his students.
He was the person to discover the electron.
1808 - John Dalton
He concluded that various compounds were combinations of atoms of different elements, each different sizes and masses.
He also concluded that these atoms could not be created nor destroyed.
Dalton sought to challenge Aristotelian theory.
He showed that common substances always broke down into the same elements in the same proportions.
1926 - Erwin Schrödinger and Werner Heisenberg
They showed it was impossible to determine where an electron was at a certain time.
They made the electron-cloud model, where the electrons existed around a certain cloud, or area, moving around the nucleus
1911 - Ernest Rutherford
He was also the first scientist to discover the nucleus.
He concluded that atoms were made out of empty space, with electrons surrounding a positively charged nucleus.
He investigated atoms by shooting positively charged particles at a sheet of gold foil. What he discovered was that some of the particles shot back out of the gold foil.
1913 - Neils Bohr
Stipulated that electrons orbit the nucleus at certain energy levels.
Also said that electrons could move across energy levels, but electrons only stayed in orbits.
He used Max Planck's and Albert Einstein's work to make his model.