Atomic Theory Timeline

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What is the Atomic Theory?

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The Atomic Theory is a scientific theory that states that matter is composed of discrete units called atoms. It explains the nature of matter and its interactions.

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Who proposed the first Atomic Theory?

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John Dalton proposed the first Atomic Theory in the early 19th century.

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What are the main postulates of Dalton's Atomic Theory?

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1. All matter is made of atoms. 2. Atoms are indivisible and indestructible. 3. All atoms of a given element are identical in mass and properties. 4. Compounds are formed by a combination of different kinds of atoms.

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What did JJ Thomson discover?

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JJ Thomson discovered the electron in 1897.

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What model of the atom did JJ Thomson propose?

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JJ Thomson proposed the 'Plum Pudding Model' of the atom, where negative electrons are embedded in a positively charged sphere.

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Who discovered the nucleus of the atom?

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Ernest Rutherford discovered the nucleus of the atom in 1911.

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What experiment did Rutherford conduct to discover the nucleus?

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Rutherford conducted the Gold Foil Experiment, where he bombarded a thin gold foil with alpha particles.

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What were the findings of the Gold Foil Experiment?

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The Gold Foil Experiment showed that most alpha particles passed through the foil, but some were deflected, indicating a small, dense nucleus.

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Who discovered the neutron?

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James Chadwick discovered the neutron in 1932.

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What is the charge of a neutron?

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A neutron has no charge; it is neutral.