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460
Democritus
Democritus was born in 460 BC and died 370 BC at the age of 90. Democritus had a theory that everything was made of atoms and that atoms are physically, but not geometrically, indivisible, that empty space is between atoms, atoms are indestructible, are always in motion, that there is an infinite amount of atoms and kinds of atoms that differ in shape and size of the mass of atoms. Democritus said "The more any indivisible exceeds, the heavier it is." -
Jan 1, 600
Acharya Kanada
It is Unclear of when Acharya Kanada was born or when he died. Some say Acharya Kanada was born 6th Century BC while others say 2nd Century BC. Acharya Kanada classified every object of creation into nine different elements (earth, water, light, wind, ether, time, space, mind and soul) and stated "Every object of creation is made of atoms which in turn connect with each other to form molecules." -
Jan 1, 624
Thales
Thales lived in Miletus between 624-546 BC. Thales believed that the origin of all matter is water. Although odd it has a little truth to it as oxygen in H2O was only created when our Earth was, helping to bring life into existence. -
Robert Boyle
Robert Boyle was born 25/1/1627 in Ireland and died on the 30/12/1691 in London. Robert Boyle helped develop the definition of an element and how if substances can be broken into 2 or more substances it is not an element. Robert Boyle also helped prove the theory of the four elements was wrong. -
Antoine Lavoiser
Antoine Lavoiser was born 26/8/1743 in Paris and died 8/5/1794 in place de la Concorde. Antoine Lavoisier believed that an element was a substance that couldn’t be broken down and that mass could not be destroyed or created and that it would just be rearranged in space. -
John Dalton
John Dalton was born on the 6/4/1766 in Eaglesfield, England and died 26/7/1844 in Manchester, England. John Dalton was the first to create a chart of atomic weights. John Dalton introduced his belief that atoms of different elements could all be distinguished by their different atomic weights. Dalton became the first person to explain the behaviour of atoms by a measurement of weight and discovered that atoms couldn't be created or destroyed. -
Joseph John Thomson
J.J Thomson was born on 18/12/1856 in Cheetham Hill (a suburb of Manchester) and died 30/8/1940. J.J Thomson was the first to suggest that the fundamental unit was over 1000 times smaller than an atom, suggesting that their where subatomic particles known as electrons. J.J Thomson imagined an atom as a sea of positive charge with these corposcules orbiting inside it (plum pudding theory). -
Ernest Rutherford
Ernest Rutherford was born on the 30/8/1871 in Spring Grove and died 19/10/1937 in Cambridge. As Ernest Rutherford investigated the scattering of alpha rays and the shape of the atom, which caused so much scattering, he discovered the nucleus. According to Rutherford the whole mass of the atom and its positive charge was concentrated in a minute space at the centre of the atom. this told us that J.J Thomsons theory was incorrect and showed us what an atom might look like. -
Niels Bohr
Niels Bohr was born on the 7/10/1885 in Copenhagen, Denmark and died 18/11/1962 in his home town. Bohr created a model of the atom on the basis of Ernest Rutherford’s ideas and concepts borrowed from the quantum theory which was quite a success and had later improvements by Heisenberg’s ideas. Bohrs model without improvements can still be used as an elucidation of the physical and chemical properties of elements. -
Erwin Schrodinger
Erwin Schrodinger was born on the 12/8/1887 in Vienna and died 4/1/1961 in Vienna. Erwin Schrodinger won a nobel prize for his introduction of the Schrodinger’s wave. This wave is a non-realistic wave equation that governs how electrons behave within a hydrogen atom. This helped us to understand more on an electrons behaviour. -
Henrey Moseley
Henry Moseley was born 23/11/1887 in Weymouth, Dorset and died 10/8/1915 in Gallipoli. Henry Moseley from his measurements of wavelengths of X-ray spectra lines through different elements managed to order elements by their atomic number. This ordering fixed all previous problems with the periodic table. -
James Chadwick
James Chadwick was born on 20/10/1891 in Bollington and died 24/2/1974 in Cambridge. James Chadwick discovered a new unknown particle In an atom that is now known as the neutron by using alpha rays to bombard Beryllium. -
Werner Heisenberg
Werner Heisenberg was born on the 5/12/1901 in Würzburg,Germany and died on 1/2/1976 of cancer. Werner Heisenberg interpereted the behaviour of electrons and subatomic particles by using parts of the quantum theory and mathematics. Heisenberg Also helped to contribute to the electron cloud model where the cloud represents the area where electrons can be found. -
Aristotle
Aristotle was born 384 BC in Stagira and died 322 BC in Chalcis. Aristotle had a theory that all matter was made of four elements: Earth, Fire, Water and air. He also believed that there were 4 qualities to these elements such as fire being dry and hot. -
Empedocles
Empedocles was born 490 BC in Agrigento and died 430 BC in Mount Etna. Empedocles believed that all matter/particles in the universe were made up of different combinations and proportions of the four elements (Earth, fire, water and air).
