Planetary model of the atom

Definition

The planetary model of the atom, proposed by Niels Bohr in 1913, depicts electrons orbiting a central nucleus similar to how planets orbit the sun. It introduced quantized electron orbits to explain atomic stability and spectral lines.

5 Must Know Facts For Your Next Test

1. Niels Bohr developed the planetary model based on Rutherford's earlier nuclear model and Planck's quantum theory.
2. In this model, electrons occupy fixed energy levels or orbits around the nucleus without radiating energy.
3. Electrons can jump between these discrete orbits by absorbing or emitting specific amounts of energy (quanta).
4. The model successfully explained the line spectra of hydrogen but had limitations for more complex atoms.
5. Bohr's postulates included quantized angular momentum and defined stable electron orbits.

Review Questions

• What are the key features of Bohr's planetary model of the atom?
• How does Bohr’s model explain the emission spectra of hydrogen?
• What limitations did scientists find in Bohr’s planetary model when applied to atoms other than hydrogen?

Related terms

Quantum Theory: A fundamental theory in physics that describes nature at the smallest scales, such as atomic and subatomic levels, including quantization of energy.

Rutherford Model: An atomic model proposed by Ernest Rutherford where a small, dense nucleus is surrounded by electrons; it led to the development of Bohr’s planetary model.

Energy Levels: Discrete levels of energy that electrons can occupy in an atom according to quantum mechanics; also known as electron shells.