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475 BCE
Ancient Greeks
Empedocles was born in 494 BCE. He thought of the theory of which there were only 4 elements; earth, air, fire, and water and how everything was made up of a combination of these four elements. Democritus was born in 460 BCE. He thought of the theory that everything was made up of atoms that were indivisible and between the atoms, there is empty space. -
John Dalton
He has created the John Dalton atomic theory which states that all matter is made of small definite particles called atoms, that atoms are indestructible and indivisible, that all atoms all atoms of one element share the properties and weight, that atoms of different elements would have a different mass, and that compounds formed from different atoms of different elements would would lead to whole number ratios. -
J.J. Thomson
He is credited with the discovery of there being negatively charged particles in an atom that were discovered as electrons. He proposed that these electrons were much smaller than atoms and he also created the plum pudding model for the atom. This changed how people would see the atom as instead of it being only a sphere, it would have electrons too. -
Marie Sklodowska Curie
She would become the first woman to win a Nobel Prize and the first person to win the Nobel Prize twice. She experimented with different rays and discovered polonium in 1898 and radium in 1902. She experimented with uranium rays and discovered that the rays would come from the atomic structure of the element -
Albert Einstein
Albert Einstein proposed the theory of relativity which combines his theory of general relativity and special relativity which explains the law of gravitation and how it relates to other forces of nature and created the equation E=MC^2 and discovered that small atoms could have the potential to be converted into large amounts of energy. -
Ernest Rutherford
Ernest Rutherford discovered that there was such thing as a nucleus in atoms. He experimented with radio waves and electromagnetic waves which led him to the discovery of protons and electrons because of how he noticed that there were particles that would bounce off of foils and particles that would penetrate through them. -
Niels Bohr
He discovered that the electrons in an atom travel in orbits around the nucleus that are separate from each other and that in the valance shell, the amount of electrons there are there would determine the properties of the element. He discovered the Bohr-Rutherford model of an atom in 1913 with the help of Ernest Rutherford, his mentor, showing electrons orbiting around a positively charged nucleus with electrons on different shells. -
Max Planck
He was a German physicist that discovered the quantum theory of energy. He thought that everything had energy waves that came off in packets where high amounts of energy with high frequency waves consisted of large packets and low amounts of energy with low frequency waves would have small packets. These waves and the frequency would be noticed as temperature. -
Louis de Broglie
Louis de Broglie was a physicist that well known for his studies on predicting the wave nature in electrons. He theorized that there were wave like properties and particle like properties in electrons and that electrons would be following this wave like pattern when orbiting a nucleus in an atom. -
Wolfgang Pauli
Wolfgang Pauli added new knowledge to the Bohr atomic model while adding two new quantum numbers and also created the Pauli principal where it states that there could not be two electrons in an atom that have the same identical sets of quantum numbers. It was later discovered that this same rule applied to protons and neutrons. -
Erwin Schrödinger
Erwin Schrödinger was a physicist that used mathematical equations to help find where elections were likely to be found. He had take Bohr's model of the atom and advanced it to become the quantum mechanical model of the atom that predicts the odds of the location of an electron that orbits the atom. -
Werner Heisenberg
Werner Heisenberg discovered the uncertainty principal where it states that it is impossible to know a particle's position and momentum to its exact place with the combined uncertainty to be greater than or equal to the equation h/(4π), where the h value is Planck's constant -
James Chadwick
He was the first one to prove that there were something called neutrons which didn't have any electrical charge that existed inside the nucleus. -
Hideki Yukawa
Hideki Yukawa was a Japanese physicist that predicted that in an atom, there is a relationship between the range and the force holding together the protons and the neutrons. He also predicted that there was an atom would have the mass 200 times greater than that of the electron. This atom would later be known as a meson. -
Rosalind Franklin
She discovered the molecular structure of DNA with the help of studying x-rays and observing the x-ray diffraction patterns. She would also help discover the molecular structure of coal and carbon that helped develop strong carbon fibers which would later on lead to nuclear power plants being able to use this for slower reactions. -
Richard F.W. Bader
Richard F.W Bader was a Canadian chemist that is well known for his expanding of quantum mechanics to open systems and for publishing his book Atoms in Molecules: A Quantum Theory (The International Series of Monographs on Chemistry, No 22) that talks about the quantification of the theory behind structures and molecular bonding.
