Multiple choice

What is Niels Bohr’s contribution to modern atomic theory?

  1. Electrons exist outside of the nucleus.

  2. Electrons have a negative charge.

  3. Electrons are found in specific energy levels.

  4. Electrons exist in regions of space called orbitals.
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C Correct answer
Explanation

Niels Bohr proposed that electrons travel around the nucleus in circular orbits at specific, quantized energy levels. This was a major advancement from previous models, though it was later refined into the electron-cloud model.

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