Chemistry Timeline

Democritus

460

Democritus was the first person to believe matter is not infinitely divisible. He also believed atoms could not be created, destroyed, or further divided

Columbus lands in the Bahamas

Oct 5, 1492

Spanish explorer Christopher Columbus lands in the Bahamas.

Benjamin Franklin invents the lightning conductor

Oct 5, 1759

John Dalton

Oct 5, 1766

John Dalton believed all matter is composed of extremely small particles (atoms) and all atoms are identical. Also, he thought atoms cannot be destroyed or created.

Antonie Lavosier

Oct 5, 1778

Antonie Lavosier, or the “Father of modern chemistry” recognized/named oxygen and hydrogen and also helped construct the metric system.

U.S. Constitution Written

Oct 5, 1787

Joseph Proust

Oct 5, 1799

Joseph Proust discovered the law of constant composition.

Amadeo Avagadro

Oct 5, 1808

Amadeo Avagadro is known for Avogadro’s Law, stating the relationship between the masses of the same volume of different gases correspond to the relationship between their respective molecular weights.

Abraham Lincoln becomes president of the United States

Oct 5, 1860

1860- Abraham Lincoln becomes president of the U.S.

William Crookes

Oct 5, 1861

Discovered thallium

Battle of Gettysburg

Oct 5, 1863

Ernest Rutherford

Oct 5, 1871

Ernest Rutherford discovered alpha and beta rays, set laws of radioactive decay, and identified alpha particles as helium nuclei. https://www.youtube.com/watch?v=Xb9KnwadI6Y

Thomas Alva Edison creates the electric light bulb

Oct 5, 1879

Max Planck

Oct 5, 1890

Max Planck found a deduce relationship between the energy and the frequency of radiation.

J.J Thomson

Oct 5, 1897

J.J Thomson showed that cathode rays consist of particles, electrons that carry electricity. He also concluded electrons are part of the atom https://www.youtube.com/watch?v=IdTxGJjA4Jw

Madame Curie

Oct 5, 1898

Madame Curie discovered radioactivity.

Henri Becquerel

Oct 5, 1903

Henri Becquerel discovered radiology with Marie Curie.

Albert Einstein

Oct 5, 1905

Albert Einstein worked with Brownian movement and developed a statistical molecular theory of liquids. https://www.youtube.com/watch?v=l-1Z2wi2uSA

Robert Millikan

Oct 5, 1910

Robert Millikan proved quantity is constant for all electrons and demonstrated the atomic structure of electricity.

Henry Moseley

Oct 5, 1913

Henry Moseley published the results of his measurements of the wavelengths of the x-ray spectral lines of multiple elements by atomic number.

Niels Bohr

Oct 5, 1913

Niels Bohr proposed a theory for the hydrogen atom based on quantum theory saying electrons move around nucleus. The heory could explain why atoms emitted light in fixed wavelengths. https://www.youtube.com/watch?v=ZkNPBy2i0ss

19th Amendment ratified, women were given the right to vote

Oct 5, 1920

Louis deBrogile

Oct 5, 1924

Louis deBroglie discovered the wave nature of electrons and suggested that all matter has wave properties.

Werner Heisenberg

Oct 5, 1925

Werner Heisenberg created theory of quantum mechanics

Erwin Schrodinger

Oct 5, 1926

Erwin Schrodinger formulated wave equation that accurately gave the energy levels of atoms.

James Chadwick

Oct 5, 1932

James Chadwick showed that in the reaction, a neutral particle with a mass about that of a proton was emitted. Discovered the neutron. https://www.youtube.com/watch?v=73JJRLd8Yio

Berlin Wall built

Oct 5, 1961

Apollo 11

Oct 6, 1969

Man takes the first steps on the Moon

First Apple II home computer is sold

Oct 5, 1977

Cold War ends

Oct 5, 1989

Hurricane Katrina hits U.S.

Oct 5, 2005

Aristotle

Mar 2, 2022

Aristotle rejected atomic theory because it did not agree with his ideas on nature. He also did not believe “nothingness” of empty space could exist.