Atomic Theory Time Travel Mission Timeline

Scientist

Democritus

460 BC - 370 BC

He was an Ancient Greek philosopher born in Abdera, Thrace, Greece. He was an influential pre-Socratic philosopher and pupil of Leucippus, who formulated an atomic theory for the universe.

Lavoisier

1743 - 1794

He was a French nobleman. He named both oxygen and hydrogen and predicted silicon. He helped construct the metric system, put together the first extensive list of elements, and helped to reform chemical nomenclature.

Proust

1754 - 1826

Joseph studied chemistry in his father’s shop and later came to Paris where he gained the appointment of apothecary in chief to the Salpetriere. He also taught chemistry with Pilâtre de Rozier, a famous aeronaut. His largest accomplishment was creating elements from water.

Dalton

1766 - 1844

He was an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory, and his research into colour blindness.

Mendeleev

1834 - 1907

He was a Russian chemist and inventor. He created the first version of the periodic table of elements, and used it to predict the properties of elements yet to be discovered.

Thomson

1856 - 1940

He was a British physicist that discovered eletrons and isotopes.

Marie Curie

1867 - 1934

was a Polish-born physicist and chemist, working mainly in France, who is famous for her pioneering research on radioactivity. She was the first woman to win a Nobel Prize, the only woman to win in two fields, and the only person to win in multiple sciences.

Millikan

1868 - 1953

He was an American physicist who measured the charge of the electron, proving Einstein's photoelectric equation.

Rutherford

1871 - 1937

Ernest Rutherford was a New Zealand chemist who helped pioneer nuclear physics. He won a Nobel Prize in chemistry, made numerous contributions to science and worked closely with a number of his students who went on to make their own significant discoveries.

Bohr

1885 - 1962

He developed the model of the atom with the nucleus at the center and electrons in orbit around it, which he compared to the planets orbiting the sun.

Moseley

1887 - 1915

The British physicist, Henry Moseley is known for his establishment of truly scientific basis of the Periodic Table of the Elements by sorting chemical elements in the order of their atomic numbers. In his short career, he contributed a lot towards the science of physics through his research. Many scientists believe that if Moseley had survived a bit longer he would have contributed a great deal to the knowledge of atomic structure and also earned the Nobel Prize in Physics.

Schrodinger

1887 - 1961

He was an Austrian physicist who developed a number of fundamental results in the field of quantum theory.

Chadwick

1891 - 1974

He was a scientist who made many contributions to the atom he was the one who discovered the neutron.

Experiments

Cathode Ray Tube Experiment

1897

It is a vacumm tube containing an electron gun and a fluorescent screen used to view images.

Gold Foil Experiment

1909

It was an experiment created by Rutherford. It helped describe the nuclear structure of the atom.

Atomic Models

Plum Pudding Atomic Model

1904

In this model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged "plums" surounded by postively charged "pudding"

Rutherford Model

1911

It was a planetary model of the atom which put all the protons in the nucleus and the electrons orbited around the nucleus like planets around the sun.

Bohr Planetary Model

1913

In the Bohr Model the neutrons and protons occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun

Quantum Mechanical Model

1926

The quantum mechanical model of the atom uses complex shapes of orbitals (sometimes called electron clouds), volumes of space in which there is likely to be an electron. So, this model is based on probability rather than certainty.

Atomic Theories

Law of Conservation of Mass

1789

Law that states that mass is neither created or destroyed in ordinary chemical and physical changes.

Law of Definite Proportions

1797

Law stating that every pure substance always contains the same elements combined in the same proportions by weight.

Dalton's Atomic Theory

1803

It was the theory that matter consists of indivisible particles called atoms and that atoms of a given element are all identical and can neither be created nor destroyed. Compounds are formed by combination of atoms in simple ratios to give compound atoms (molecules).