Chemistry Timeline - 5th period

Aristotle

420

Aristotle disagreed with Democritus's belief. The belief of atoms was banished.

Sir Robert Boyle

Oct 13, 1637

Formulated the fundamental gas laws. First to propose the combination of small particles to form molecules. Differentiated between compounds and mixtures.

James Bradley

Oct 14, 1728

Uses aberration of starlight to determine the speed of light to within 5%. accuracy.

CarlWilhlm Scheele

Oct 14, 1742

Discovered chlorine, tartaric acid, metal oxidation, and sensitivity of silver compounds to light (photochemistry).

Benjamin Franklin

Oct 14, 1752

Demonstrated that lightning is electricity.

Joseph Priestley

Oct 14, 1767

Discovered oxygen, carbon monoxide, and nitrous oxide. Proposed electrical inverse-square law

Thomas Young

Oct 14, 1801

Demonstrated the wave nature of light and the principle of interference.

Nicholas Le Blanc

Oct 14, 1806

Invented process for making soda ash from sodium sulfate, limestone and coal.

John Dalton

Oct 13, 1808

Dalton revived the idea of the atom. When the atoms form together, they grow into crystal.

Amedeo Avogadro

Oct 13, 1811

He explained how different atoms had a fixed proportion. He also found that when atoms break up they are called molecules.

Antoine Henri Becquerel

Oct 13, 1896

Becquerel discovered that some metals were radioactive. He discovered it by accident.

Marie & Pierre Curie

Oct 13, 1898

Marie & Pierre Curie discovered Radium. Marie was the first person to win a Nobel Prize for two ideas. They died by radium.

Joseph John Thomson

Oct 13, 1904

Thomson, physicist, inferred from his experiments that atoms contained negatively charged particles. He thought these electrons were evenly embedded throughout a positively charged sphere.

Albert Einstein

Oct 13, 1905

Einstein discovered a new law. His theory showed that every mass had a great amount of energy.

Ernest Rutherford

Oct 13, 1911

He figured that the atom is mostly empty space. He showed that radium/radiation can pass through atoms. And every thousand atoms the radiation hits something solid.

Bohr Model

Oct 13, 1913

Danish physicist, Niels Bohr, hypothesized that electrons traveled in fix orbits around the atom's nucleus. James Chadwick, a student of Rutherford, concluded that the nucleus contained positive protons and neutral neutrons.

Electron Cloud of Probablity

Oct 13, 1917

According to the currently accepted model of atomic structure, electrons do not follow fixed orbits but tend to occur more frequently in certain areas around the nucleus at any given time.

Lavoisier, A.L

Oct 14, 2013

Discovered nitrogen. Described the composition of many organic compounds. Sometimes regarded as the Father of Chemistry.

Count Rumford

Oct 14, 2013

Thought that heat was a form of energy.

Democritus

Mar 2, 2022

He was the fist person to believe that all things were made of tiny atoms.