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John was born in Eaglesfield, England on 6/9/1766.
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He revived the atomic theory. He created Dalton’s law (gasses), Daltonism (colour blindness) and many other scientific discoveries. Dalton's atomic theory is :
1. All matter is made up of atoms2. Atoms are indivisible and indistructable
3. Compounds are formed by combining two or more different atoms Dalton’s theory became the foundation of atomic information and study. -
Dmitri Mendeleev was born in Tobol’sk, Siberia on 7/2/1834
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He died on 27/7/1844 of a stroke at age 77.
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JJ Thomson was born on 18/12/1856 in Cheetham Hill, Manchester.
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Mendeleev Created the first ever periodic table of elements, because the current way of calculating atomic weight was incorrect. He did it by looking at the chemical properties of elements and arranging the elements by their properties. He listed them in ascending order of atomic mass, and arranged them so elements with similar properties were close. There were gaps so he predicted three new elements, Gallium, Scandium and Germanium. There were 66 elements in the final table.
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He created the first periodic table ever. He also predicted the existence of new elements based on the properties of the elements around the gaps in his table. This helped scientists discover new elements by using the same methods.
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Ernest Rutherford was born on 30/8/1871 in Nelson New Zealand
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Niels bohr was born in Copenahgen on 7/10/1885
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Henry Mosely was born on 23/11/1887
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James Chadwick was born in Cheshire on 20/10/1891
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Thomson discovered that all matter is made up of particles smaller than atoms. They are called electrons. He also proved the existence of isotopes in stable elements. His studies helped by discovering the electron, and proving the existence of subatomic particles, triumphing Daltons discovery saying that atoms are indivisible particles.
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Enrico Fermi was born on 29/9/1901
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He died at 72 in St. Petersburg on 2/2/1907
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Rutherford discovered that the atom has a tiny nucleus and the electrons floated around the nucleus. The Rutherford model showed us that the electrons aren’t scattered around in positively charged matted lie the Thomson model. It shows us that the electrons float around the nucleus.
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Niels Bohr’s greatest discovery was his atomic model. He was the first to realise that electrons travel in separate orbits than the nucleus and that the number of electrons in the outer orbit decide the properties of an element. The element on the periodic table bohrium (Bh) is named after him.
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He changed the atomic theory by discovering that electrons didn’t crash into the nucleus. He created the Planetary model. Niels Bohr said that the electrons absorbed photons to move to a higher energy level and released photons in specific amounts to get back to their ground state.
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Henry died on 10/8/1915 in Gallipoli
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James Chadwick discovered the neutron that is neutrally charged. They have the same mass as protons. The atom was now made up of a nucleus, protons (positively charged) and neutrons (neutral) inside the nucleus, and electrons (negatively charged) surrounding the nucleus. James showed us that there are neutrons inside the atom, as well as the protons. He also showed us that the charge was neutral.
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He died in Cambridge on 19/10/1937
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He died on 30/8/1940 . His cause of death is unspesified
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Enrico Fermi created a controlled nuclear reaction (to split an atom without creating a deadly explosion), to become a part of the atomic bomb. which was launched in 1942. Enrico contributed to the atomic theory because he found a way to split the atom, which contributed to the atomic bomb which is commonly used in nuclear power plants to this day.
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He died in Chicago in 28/11/1954
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He died on 18/11/1962
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He died on 24/7/1974
