Atomic theory History of the atom

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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, which are the fundamental building blocks of all substances.

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Who proposed the idea of atoms as indivisible particles?

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Democritus proposed the idea of atoms as indivisible particles around 400 BC.

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What did John Dalton contribute to atomic theory?

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John Dalton developed four main postulates of atomic theory, which laid the foundation for modern chemistry.

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What is J.J. Thomson known for in atomic theory?

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J.J. Thomson is known for discovering the electron and proposing the 'plum pudding' model of the atom, which describes atoms as uniform spheres of positive charge with negatively charged electrons embedded within.

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What did Ernest Rutherford discover about the atom?

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Ernest Rutherford discovered that atoms have a small, dense nucleus that contains positively charged protons, and that electrons orbit this nucleus.

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What is the Bohr model of the atom?

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The Bohr model of the atom describes electrons orbiting the nucleus at fixed energy levels, which explains the emission spectra of elements.

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What are the main components of an atom?

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The main components of an atom are protons (positively charged), neutrons (neutral), and electrons (negatively charged).

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What is the charge of an electron?

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An electron has a negative charge.

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What is the charge of a proton?

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A proton has a positive charge.

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What is the significance of the nucleus in an atom?

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The nucleus contains most of the atom's mass and is made up of protons and neutrons.