Democritus - 429 BCFirst person to think of the atom.
Thought the atom was a solid circle.
Issac NewtonTiny pieces of mass "swimming" everywhere
*(he agreed with Democritus)*
John DaltonAll matter is composed of atoms - true
Atoms cannot be made or destoryed - false; an atom can be split
by a nuclear reaction
All atoms of the same elements are idenctical - false; isotopes
Different elements have different types of atoms - true
Chemcial reactions occure when atoms are rearranged - true
Compunds are formed from atoms of different elements - true
Henri BecquerelHelped discover radioactivity
J.J ThomsonProved the existence of negatively charged atoms ( electrons )
Andrew MilikanMeasured charge and mass of electron.
RutherfordAn atom has a central positive nucleus surrounded by negative orbiting elements.
He was credited with the nucleus and proton.
BohrHis electrons are traveling in orbits.
Decided atom was a small, positively charged nucleus surrounded by electrons.
Francis AstonDiscovered isotopes of non-radioactive elements.
SchrodingerFound the atom consist of nucleus aned cloud.
Discovered the formula that calculated the odds of where the electron might be.
Proved Bohr's model incorrect.
James ChadwickDiscovered the nuetron.
Aristotle - 400 BCThought everything was made up of fire, air, earth, and water instead of atoms