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John Dalton
Dalton had a strong fascination with gases which in further detail he discovered that all gases consisted of tiny particles. Dalton made these findings into a law which is now known as Dalton’s law of partial pressures. Dalton continued he’s study and found that not only gases consisted of small particles but all matter consisted of them. Dalton called these small particles atoms. Dalton’s atomic theory states that atoms differ from each other only in mass. -
J.J.Thompson
J.J.Thompson was the discoverer of the electron. He determined that all matter is also made up of tiny particles that are much smaller than atoms, called electrons. Thompson also suggested the model of the atom as a sphere of positive matter with the electrons positioned by electrostatic forces. This helped him estimate the number of electrons in an atom. Thompson also was the first person to use mass spectrometry. -
Ernest Rutherfprd
Rutherford did remarkable discoveries in the areas of radioactivity and nuclear physics. He identified a simpler mean of detecting radio waves. Rutherford worked alongside J.J.Thompson which together they worked on the study of x-rays. After departing with Thompson, Rutherford took a closer look at ion-producing radiations. In 1907 Rutherford made the discovery that almost the total mass of an atom is concentrated in a nucleus. Therefore he presupposed the nuclear structure of the atom. -
Marie Curie
Marie Curie’s fascinations with rays led to her discovery of two new elements. She thoroughly examined the rays from the uranium in a material called pitchblende and Marie expected there to be few rays, but pitchblende had many rays which she realised led to the discovery of new elements in pitchblende. One of the elements she named polonium and the other radium. -
Henry Moseley
The main contribution that Henry Moseley made to our knowledge of the atomic theory was finding the reason and understanding the theory of the atomic number. Before Henrys discovery atomic numbers had been allocated to a random number on the periodic table, based on its atomic weights. In Henrys discovery he showed that the way atomic numbers were given were not at random but had an experimentally measurable basis. -
Niels Bohr
Bohr proposed the theory that energy is transferred only in certain well defined quantities. He found that electrons move around the nucleus in an orbit. He found that when the electrons jump from one orbit to another orbit that had lower energy, a light quantum is emitted. -
Francis Aston
Aston discovered the existence of two isotopes from he’s studies on the element neon. What he found was that elements can be made up of two different types of atoms. These atoms were chemically identical but of different mass (Isotopes). He's findings led him to create the whole number rule which states: "the mass of the oxygen isotope being defined, all the other isotopes have masses that are very nearly whole numbers." -
Erwin Schrodinger
Due to Niels Bohr’s discovery from the hydrogen atom, there needed to be a further development for more complicated atoms and molecules. Schrodinger established that matter could be regarded as both particles and waves. This formulated Schrodinger to create a wave-equation that accurately gave the energy levels of atoms. -
James Chadwick
After Rutherford’s discovery of nucleus holding a positive charge in the hydrogen nucleus, Chadwick wanted to discover where the extra mass was living. When doing this he discovered the neutron. In the experiment that he conducted to discover the neutrons his results showed a collision with beryllium atoms that would release massive neutral particles known as ‘neutrons.’ -
Murray Gell-Mann
Gell-Mann discovered the theory that the nucleus of an atom consists of about 100 fundamental building blocks, which he called quarks. This finding was one of two fundamental ingredients for all matter in the universe.
