-
460 BCE
democritus
He theorized that all material bodies are made up of indivisibly small atoms. -
428 BCE
plato
he was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school. -
332 BCE
aristotle
Aristotle was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato. -
lavoisier
Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen and hydrogen. -
the Alchemists
The alchemists believed that all metals were formed from two principles — mercury and sulfur. -
john dalton
Dalton's atomic theory suggested that all matter was comprised of indivisible and indestructible atoms with distinct masses and properties -
new lands law of octaves
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. -
mendeleevs pd. table
Dmitri Mendeleev, a Russian chemist and teacher, devised the periodic table a comprehensive system for classifying the chemical elements. -
albert einstein
Albert Einstein was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. -
photoelectric effect
phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation -
discovery of radioactivity
Henri Becquerel Discovers Radioactivity. In one of the most well-known accidental discoveries in the history of physics -
discovery of the electron
During the 1880s and '90s scientists searched cathode rays for the carrier of the electrical properties in matter -
discovery of the proton
The proton was discovered by Ernest Rutherford in the early 1900's. During this period, his research resulted in a nuclear reaction which led to the first 'splitting' of the atom. -
plancks quantum theory
According to Planck's quantum theory, Different atoms and molecules can emit or absorb energy in discrete quantities only. -
plum pudding model
the pludding model is a historical scientific model of the atom. The plum pudding model is defined by electrons surrounded by a volume of positive charge -
charge of the electrons
electron, lightest stable subatomic particle known. It carries a negative charge of -
rutherfords gold foil experiment
A piece of gold foil was hit with alpha particles, which have a positive charge. Most alpha particles went right through. This showed that the gold atoms were mostly empty space. -
bohrs planetary model
the electrons encircle the nucleus of the atom in specific allowable paths called orbits. -
mosleys atomic numbers
In 1914 Moseley published a paper in which he concluded that the atomic number is the number of positive charges in the atomic nucleus -
heisenberg uncertainty principle
we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy; -
discover of the neutron
In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron. Chadwick was born in1891 in Manchester, England. -
robert millikan
Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil-drop experiment. -
schrodinger equation
The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system.
