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John Dalton
Discovered the theory that atoms and elements could be recognised by their different characteristics and weight. This theory led him state basic ideas of, all matter is composed of atoms, which cannot be made or destroyed, different elements have different types of atoms and all atoms of the same element are identical. -
J.J Thomson
From 1897 to 1904, he invented the plum pudding model which allowed him to discover the electron in a series of experiments. From this he discovered the cathode rays which are negatively charged particles which are called ‘corpuscles’, then he found out that mass was about 1000 times smaller than a hydrogen atom. -
Marie Curie
Curie was the first person to receive two Nobel Prizes, one which was shared with her husband for their discovery of radioactivity in 1903. She was then recieved another Nobel Prize for her for her discovery of radioactive elements of polonium and radium in 1911 -
Ernest Rutherford
He made up his own atomic theory describing the atom has a central positive nucleus surrounded by negative orbiting electrons. This recommended that most of the mass of the atom was made up of empty space. From this theory he invented the famous “Gold Foil Experiment.” This wanted to fire radioactive particles through metal foils. This then allowed him to lead him to his theory that most of the atom was constructed of mostly empty space. -
Niels Bohr
Niels Bohr explained what was inside an atom, and what was happening in it, this allowed him to develop a picture of atomic structure in 1922. From this he discovered that the nucleus has electrons traveling around it in separate orbits, and that the number of electrons in the outer orbit, can define the resources of an element. “Bohrium (Bh), No.107”, on the periodic table is the element named after him. -
Henry Moseley
In 1913 he arranged chemical elements in the order of their atomic numbers. While at University, he discovered the X-Ray spectra, through this he discovered a relationship between wavelength and atomic number.This theory helped him and others to explain the elements on the periodic table by just using this atomic number.
Famous Scientists, 2013, Henry Moseley, website, viewed 12th September 2013, http://www.famousscientists.org/henry-moseley/ -
Francis Aston
He invented the mass spectrograph, from this he observed isotope. From this he discovered that for several elements the atomic mass is not the mass of all atoms of the element. For example the atoms had a mass number of 1, with that he also found out that hydrogen atoms with mass numbers of 2 and 3. His work let Rutherford to make his own discoveries. -
Erwin Schrödinger
From Niels Bohr atom model, Schrodinger took this to another level, using mathematical equations to put an electron into a certain position, this is called the “Quantum Mechanical Model of the Atom.” This didn’t tell us the exact pathway of the electron but can tell us a prediction of the location of it. -
James Chadwick
James Chadwick discovered the existence of neutrons, which was the fourth subatomic particle, this joined electrons and protons, he found that neutrons has an equal mass to the protons. -
Murray Gell-Mann
(1950's-1960's)
Gell-Mann discovered the strangeness theory, this allowed him to group the known particles by electrical charge and their “strangeness” number. They would usually be categories in group of eight and divides in octets, this then was brought together in the system called “The eightfold way”.
