Atomic Theory Timeline

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What is the main idea of Dalton's Atomic Theory?

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Dalton's Atomic Theory states that all matter is made up of atoms, which are indivisible and indestructible particles. Atoms of the same element are identical, and they combine in simple whole-number ratios to form compounds.

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Who proposed the first modern atomic theory?

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John Dalton proposed the first modern atomic theory in the early 19th century.

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What did Thomson discover about the atom?

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Thomson discovered the electron, a negatively charged particle, and proposed the 'plum pudding' model of the atom, where electrons are embedded in a positively charged 'soup'.

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What is Rutherford's model of the atom?

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Rutherford's model describes the atom as having a small, dense nucleus that contains protons, with electrons orbiting around it, similar to planets around the sun.

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What is the Electron Cloud Model?

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The Electron Cloud Model describes the atom as having a nucleus surrounded by a cloud of electrons, where the exact position of electrons cannot be determined, only the probability of finding them in certain areas.

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What is an element?

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An element is a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom.

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What is a compound?

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A compound is a substance formed when two or more different elements chemically bond together in fixed proportions.

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What did Bohr contribute to atomic theory?

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Bohr proposed that electrons travel in specific orbits around the nucleus and that these orbits correspond to specific energy levels.

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What is the significance of the atomic number?

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The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity and its position on the periodic table.

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What is the difference between an atom and a molecule?

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An atom is the smallest unit of an element, while a molecule is a group of two or more atoms bonded together.