Atomic Theory Means there is a link on the page. Click on the image
John Dalton (1800) Pure elements consist of atoms. Atoms of an element are all the same for that element. (all gold atoms are the exact same) Atoms can be told apart by their atomic weights. Atoms unite to form chemical compounds. Atoms can neither be created or destroyed in chemical reaction.
J.J. Thomson (1850) Cathode Ray Tube Experiment Discovered negatively electrons Plum pudding model https://www.youtube.com/watch?v=XU8nMKkzbT8&feature=related
Ernest Rutherford (1905) Gold foil experiment Discovered that: Atoms are mostly empty space Atoms have a nucleus (positively charged) Electrons move around nucleus at distance Nuclear atom model https://www.youtube.com/watch?v=Q8RuO2ekNGw
Niels Bohr (1920) Electromagnetic Spectrum the entire spectrum, considered as a continuum, of all kinds of electric, magnetic, and visible radiation https://www.youtube.com/watch?v=cfXzwh3KadE
Waves Wavelength: distance from crest to crest Short wavelengths = higher energy Amplitude: distance from level of crest to level of trough wavelength amplitude
Waves Frequency: number of crest passages per unit time Higher frequency = higher energy https://www.youtube.com/watch?v=7Iv4GmyXsCQ
Electromagnetic Spectrum https://www.youtube.com/watch?v=wbbsbE2mQuA ROYGBV
Invisibility Cloak Infrared waves Object https://www.youtube.com/watch?v=oLbS3M4V7oI&feature=watch_response
Niels Bohr (1920) Studied energy emissions from hydrogen Continuous spectrum: all visible light waves present versus Bright line spectrum: certain (discrete number of) visible light waves present https://www.youtube.com/watch?v=QI50GBUJ48s
Niels Bohr (1920) Studied energy emissions from hydrogen Electrons can only exist on definite energy levels that are specific distances from the nucleus. Planetary model Draw arrows of energy
Current Model of Atom
Quantum Mechanical Model Mathematical model The model estimates the probability of finding an electron in a certain position https://www.youtube.com/watch?v=xqNSQ3OQMGI Denser area = higher chance of finding an electron