-
400 BCE
democritus
he was know to be one of the people who made the ancient atomist theory -
201 BCE
plato
he is a philosopher that is known for a theory known as Platonism where he believed that the existence of a immortal world and perfect objects -
330
Aristotle
he was a philosopher and in one of his metaphysics he said "there must be a separate and unchanging being that is the source of all other beings." -
Lavoisier
Antoine Lavoisier, a French chemist known as "the father of modern chemistry" found out that oxygen in combustion and respiration, reformed the chemical nonculture, and named hydrogen. -
the alchemist
the alchemist believed that metal is only formed from two principles sulfur and mercury -
John Dalton
he was a schoolteacher, a meteorologist, and an expert on color blindness he also made ways to calculate atomic weights, structures, and also formulated the law of partial pressure. -
Mendeleev's pd. table
medeleev's table was a failed table but the way he made it was that the elements are in order from increasing weight and broken into rows -
newlands law of octaves
this law states that when elements are arranged in increasing order of atomic mass the properties of every eighth element starting from any element are a repetition of the properties of the starting element -
discovery of radioactivity
French physicist Pierre and Maria discovered that uranium minerals have radium and polonium elements have them in it and there highly radioactive -
Photoelectric effect
the effect is a phenomenon were electric charged particles are released from a when it absorbs electromagnetic radiation. -
discovery of electrons
J.J Thompson was the first to discover electrons with cathode ray tubes which later contributed to the atom split -
discovery of the proton
Ernest Rutherford discovered the proton when he split a atom for the first time -
Plancks quantum theory of light
a light bulb should be heated to a temp of 3,200 Kalvin to ensure the energy is emitted to visible waves -
plum pudding model
the plum pudding model also known as Thompson's plum theory is defined by electrons surrounded by a volume of positive charge -
charge of the electron
Robert Millikan was the on who discovered the charge of a electron by using negatively charged oil drops charge (e) of an electron is à − 1.60 à — 10 − 19 Coulombs. -
Rutherford's gold foil experiment
the experiment showed a atom is basically empty with a tiy dense positively charged nucleus. -
bohrs planetary model
it was the first model that showed electrons orbit the outside nucleolus. -
Mosley's atomic numbers
Mosley is the one that said that the atomic number is the number of positive charge in a atom -
schrodinger equation
its a linear differential equation that governs a wave function of a quantum mechanical system in 1926 Erwin Schrödinger formulated it -
Heisenberg uncertainty principle
this principle was made by German physicist Nobel laureate Werner Heisenberg it say that we are not able to know the speed and position of a particle such as a photon or electron with perfect accuracy -
Discovery of the electron
German physicist Heart Becker and Walther Bothe saw that if you penetrate a form of radiation when the alpha particles emitted polonium was incident on relatively light elements such as lithium beryllium and boron