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How does the quantum model of the atom describe the position of an electron, compared with Bohr's model of fixed circular orbits?
AAs a fixed point that never moves once measured
BAs identical to Bohr's circular orbit, with no changes at all
CAs a straight line connecting the electron to the nucleus
DAs a cloud of probability rather than a fixed, well-defined orbit
Answer & Solution
Correct answer: D. As a cloud of probability rather than a fixed, well-defined orbit
1. Bohr's model assumed electrons follow simple, well-defined circular orbits.
2. The quantum model instead describes the electron's position as a cloud of probability built from repeated measurements.
3. The electron is not fixed at one point once measured, since repeated measurements scatter across the cloud.
4. This differs from Bohr's fixed circular orbit, so calling the two identical is wrong.
5. A straight line to the nucleus is not how either model describes the electron.
6. So a cloud of probability is correct.
_Source: OpenStax Physics (CC BY 4.0), Ch 22 "The Atom", section 22.1 The Structure of the Atom_
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