The Development of Atomic Theory

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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, suggesting that all matter is made up of atoms.

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What is the main idea of Democritus' atomic theory?

Back

Democritus proposed that matter is composed of small, indivisible particles called atoms, which are eternal and unchangeable.

Front

What does Rutherford's model of the atom describe?

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Rutherford's model describes the atom as having a small, dense nucleus surrounded by electrons, based on his Gold-Foil Experiment.

Front

What is the Plum Pudding Model?

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The Plum Pudding Model, proposed by J.J. Thomson, describes the atom as a sphere of positive charge with negatively charged electrons embedded within it.

Front

What are protons?

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Protons are positively charged subatomic particles found in the nucleus of an atom.

Front

What are neutrons?

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Neutrons are neutral subatomic particles found in the nucleus of an atom, contributing to its mass.

Front

What is the charge of an electron?

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Electrons have a negative charge.

Front

What experiment did J.J. Thomson conduct to discover the electron?

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J.J. Thomson conducted the Cathode-Ray Tube Experiment, which led to the discovery of the electron.

Front

What is the significance of the Gold-Foil Experiment?

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The Gold-Foil Experiment, conducted by Ernest Rutherford, demonstrated that atoms have a small, dense nucleus and that most of the atom is empty space.

Front

What is the Bohr Model of the atom?

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The Bohr Model describes the atom as having electrons orbiting the nucleus in fixed paths or energy levels.