-
500 BCE
The alchemists
the alchemists believed that all metals were formed from mercury and sulfur -
400 BCE
Democritus
the Democritus discovered and were the first people to think that the atom is the basic building block and that its almost invisible and always moving around. they also created the first atomic model. -
384 BCE
Aristotle
Aristotle believed that the atom was all made-up of separate tiny particles he called Atomos. he also believed in the fire air earth and water. -
5 BCE
Plato
a Greek philosopher who discovered a teaching of simple ontology of atoms. -
Lavoisier
Antoine is mostly known for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and opposed the phlogiston theory. -
John Dalton
John Dalton was an English chemist best known for introducing the atomic theory and research into colorblindness -
Newlands law of octaves
J. A.R. (john) Newland founded the law of octaves which is if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements. -
Discovery of Radioactivity
Henri Becquerel discovered Radioactivity accidentally while trying to work on x-rays. -
Mendeleev's Pd. Table
Mendeleev created a periodic table that was arranged by weight all though his table was not perfect it was good enough to be used. the thing that made his table different was the gaps he used. -
Photoelectric effect
photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. this was discovered by a German physicist named Heinrich Hertz. -
Discovery of the electron
J.J. Thompson discovered the electron by messing with cathode rays and studying particles in neon gas. -
Planck's quantum theory of light
Planck's quantum theory of light means Different atoms and molecules can emit or absorb energy in discrete quantities only. which basically means that light must carry energy in discrete quantities. -
Plum pudding Model
J.J. Thompson created the plum pudding model to try and explain two properties of atoms that electrons are negatively charged particles and Adom's have no net electric charge. -
Discovery of the proton
Ernest Rutherford discovered the proton by having a nuclear reaction causing splitting of the atom where he discovered protons because of it. -
Charge of the electron
the electron has a negative charge of -1 it was discovered by Robert millikan. -
Robert Millikan
Robert discovered the charge of an individual electron leading to the discovery all electrons carry the same amount of negative charge. -
Rutherfords gold foil experiment
Rutherford's experiment was used to show he bombarded the foil with fast moving alpha particles finding out that most of the particles went right through and the gold was no more than an empty space. -
Bohr's planetary model
Niels Bohr structural model of an Adom, the model is showing the electrons traveling around the nucleolus of the atom. -
Mosley's atomic number
Mosley discovered the atomic number and concluded the atomic number is the number of positive charges in the atomic nucleus -
Albert Einstein
albert Einstein is best known for developing the relativity theory also contributed to most other theories. -
Heisenberg uncertainty principle
the German physist and Heinsberg used the principle to show that you can't know the speed and position of a particle with perfect acuracy. -
Discovery of the Neutron
James Chadwick discovered the neutron by bombarding Beryllium with alpha particles from radioactive decay of polonium which resulted in the discovery of the neutron. -
Schrodinger equation
the Schrodinger equation is linear partial differential equation that governs the wave function of a quantum-mechanical system.