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600 BCE
Achraya Kanad
He came up with the idea that atoms are indivisible and indestructible. He also came up with the idea that an atom can be at absolute rest or a state of motion. He is believed to be one of the first to come up with the idea of the atom. This idea occurred to him while he was walking and nibbling on food. Eventually he wouldn't be able to divided and take smaller bites on the food. -
500 BCE
Alchemists
They brought the idea of deconstructing and reconstructing matter. They developed basic ideas that would later create the periodic table used in the modern day. -
460 BCE
Democritus
Democritus came up with the theory that the atom is the smallest, and indivisible part in the Universe. They are indestructible, and empty space lies between them. They are always in motion and there is an infinite amount of different kinds of atoms. This was the basic idea of the atom that was a step into understanding what the universe was made of. -
John Dalton
His theory was that everything was made up of indivisible, and indestructible building blocks called atoms. Every atom of a type was identical and different atoms had different sizes and mass. All compounds were composed of a ratio of these atoms. A chemical reaction was the rearrangement of the atoms. -
Thomson
Thomson discovered the Electron. He achieved this by using cathode ray tubes that shot negatively charged particles at a gold foil. Some of the particles were observed to be deflected in different directions. He made his own version of the atom, the plum pudding model; it had negatively charged particles on the surface of a positively charged particle. -
Max Planck
He created the quantum theory of energy. His theory helped develop a better understanding of atomic and subatomic processes. His idea was that energy was transferred in specific packets rather than a continuous, unbroken wave of energy. He came up with the universal constant called Planck’s constant. -
Hantaro Nagaoka
Developed on of the earliest models of the atom. He proposed that the center of the atom was positively charged and was surrounded by some revolving electrons. -
Albert Einstein
Proved that atoms could not only emit but absorb photons. He created the equation E=MC^2, which relates energy and mass together. This would later be used to make the atomic bomb. -
Ernest Rutherford
He proved that J.J Thomson’s model was wrong. He created his own model, the Rutherford model, that had empty space around the positively charged nucleus and electrons orbited it in fixed paths. He discovered the nucleus when aiming alpha rays at a thin gold sheet. -
Bohr
He discovered that energy is transferred in certain quantities. Electrons move around the nucleus, in specific orbits. Energy is released when they jump from atom to atom. This created the Bohr diagram that would later be improved by Rutherford to create the Bohr-Rutherford diagram. The electrons orbit the nucleus and are identified by the Principle Quantum Number and are calculated by the "2n^2 Rule" -
Marie Skiodowska Curie
Used Uranium rays to discover that they are the same with all forms and conditions of Uranium.
She and Becquerel were awarded the Nobel Prize for discovering radioactivity. She also discovered polonium and Radium with her husband. -
Satyendra Nath Bose
Predicted the existence of bosons. His idea of bosons was adopted by Einstein and a phenomenon had been discovered. It is called the Bose-Einstein Condensate. -
Louis de Broglie
He came up with the idea that matter has wave properties and properties of particles. As Mr. Jones likes to call them “wavicles”. This helped further get an understanding of quantum mechanics. -
Werner Heisenberg
His contribution was that he created the uncertainty principle; a particle’s position and momentum cannot be known exactly. He also developed quantum mechanics. -
Wolfgang Pauli
Wolfgang introduced two new quantum numbers and created the Pauli Principle. His principle states that no two electrons can have the same quantum numbers. It is the same for protons and neutrons. He also hypothesized the neutrino, which is related to quantum mechanics. -
Erwin Schrodinger
Erwin Schrodinger used mathematical equations to determine the likelihood of finding an electron at a certain point in a certain orbit. He created his own orbits that had their own shapes. His model is called the Quantum mechanical model. Its orbits are not where the electron is, more of that is where it is more likely to be. -
James Chadwick
Before his discovery, the atom was thought of having a positively charged nucleus, surrounded by electrons. He shot alpha particles at Beryllium atoms and discovered neutrons. This filled the gaps in other chemists’ work. -
Irene Curie
Irene discovered that radioactive elements can cause stable elements to become radioactive. She achieved this by emitting alpha particles to an aluminum sheet. This brought new ideas to radiochemistry and found ways to create cheaper radioactive material. -
Lise Meitner
Discovered that nuclear fission creates a huge amount of energy. This would be later used to create the atomic bomb. Some call her the mother of the atomic bomb which she does not like due to the use of the atomic bomb. -
Dorothy Hodgkin
Dorothy worked with Bernal and determined the three-dimensional structure of some important organism molecules using x-ray crystallography. X-ray crystallography was a very new technique. -
Rosalind Franklin
She worked with X-rays and made discoveries on how to prepare DNA specimen to get sharp x-ray diffraction patterns. She also made discoveries about the structure of coal and carbon that were used to create strong carbon fibers and slow reactions in Nuclear power plants. -
Robert LeRoy
“I study the sex life of molecules.”
He was known for developing the LeRoy-Bernstein theory and the LeRoy Radius. The LeRoy-Bernstein theory describes the vibration energy levels close to the dissociation limit. The LeRoy Radius is related to the theory he created and states the internuclear distance between two atoms. -
Ronald J Gillespie
He has developed many superacids, including, HSOF3. He studied the shapes of molecules. This led to the development of the Valance Shell Electron Pair Repulsion (VSEPR) theory. This theory predicts and describes the shapes of molecules based on their outer electron pairs
