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440 BCE
Plato
Plato came up with a theory that asserts the physical world isn't the only thing in existence. Instead, there is more to existence than just Earth. -
400 BCE
Democritus
Democritus was an important man to the development of the atomic theory. He theorized that all material bodies are made up of atoms. -
Robert Boyle
Robert Boyle stated that when the volume of a gas decreases the pressure increases. -
Antone Lavoisier
Antonio Lavoisier found out that the total mass and reactant in a product are always the same. This led to the Law of Construction and Mass. -
Billiard Ball Model
John Dalton thought atoms were the smallest particle of matter. He envisioned that atoms were hard solid spheres, hence he created models like a billiard ball. Dalton made it to where atoms are together and would be hooked up as a model compound. -
The Alchemists
The Alchemists broke the 4 elements durring its period. In order to do this, they laid out a foundation, which is now the periodic table. -
John Dalton
John Dalton was the man that created the atomic theory. This stated that all matter is composed of small, indestructible particles called atoms. -
Dmitri Mendeleev
Dimitri Mendeleev found out that all known chemicals would be arranged in order of increased atomic weight. This resulted in the Periodic Table being displayed are in an occurring pattern. -
Robert Millikan
Robert Millikan discovered that there is a fundamental change in a charged electron. -
Pierre and Marie Curie
Piere and Marie Curie together found out that inside uranium minerals there are strong radioactive elements in them like polonium and radium. -
Neils Bohr
Neils Bohr proposed a theory for hydrogen atoms. The theory was based on the quantum theory and stated that some physical quantities only take discrete volumes. -
Plum Pudding Model
JJ Thompson proposed the Plum Model of an atom that was negatively charged with electrons embedded in a positively charged one. -
Albert Einstein
Alber Einstein is the most famous and revolutionary scientist ever. He mathematically proved the existence of atoms. -
Ernest Rutherford
Ernest Rutherford found out that an atom is mostly made up of empty space, with almost all of its mass in the nucleus. -
Solar System Model
Neils Bohr created the solar system model for the atom. It states that atoms consist of a nucleus with a certain amount of electrons that orbit the nucleus. -
JJ Thompson
JJ Thompson demonstrated that all atoms contain tiny negatively charged subatomic particles. -
Henry G.J. Mosely
Henry G.J. Mosely found out that the atomic number in an atom is the number of positive changes. -
Erwin Schrodinger
Erwin Schrodinger showed that the quantization of hydrogen atoms energy showed up on Neils Bohr's atomic model and it could be calculated using his equation. -
Electron Cloud Model
Erwin Schrodinger made the Electron Cloud Model. This model consists of a dense nucleus that is surrounded by a cloud of electrons. -
James Chadwich
James Chadwich discovered that atoms consist of not only protons and electrons but also neutrons.
