History of Atomic Theory

Front

Who proposed the first modern atomic theory?

Back

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

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What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that mass is neither created nor destroyed during chemical reactions or physical changes.

Front

What did Democritus call the smallest particles of matter?

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Democritus called the smallest particles of matter 'atomos', which means 'uncut' or 'indivisible' in Greek.

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What particle did J.J. Thomson discover?

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J.J. Thomson discovered the electron.

Front

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.

Front

What did Rutherford's gold foil experiment demonstrate?

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Rutherford's gold foil experiment demonstrated that atoms have a small, dense nucleus that contains most of the atom's mass.

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What is the significance of the Bohr model of the atom?

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The Bohr model introduced the idea that electrons orbit the nucleus in specific energy levels.

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What is the difference between protons and electrons?

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Protons are positively charged particles found in the nucleus, while electrons are negatively charged particles that orbit the nucleus.

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What is 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.

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What is an isotope?

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An isotope is a variant of an element that has the same number of protons but a different number of neutrons.