Probability Cloud:
The probability distribution for an electron cloud is a mathematical model that shows where an electron is likely to be found around an atomic nucleus.
Due to the wave–particle duality of quantum matter, an electron can simultaneously behave as both a tiny physical particle (of mass = 9.1×10−31 kg) and an extended wave depending on how the observer measures its property.
According to the Heisenberg Uncertainty Principle, you cannot simultaneously know an electron's exact position and its momentum. Therefore we must adopt the probabilistic view of the electron's location surrounding the atomic nucleus.
The Bohr radius {5.3×10−11 m} is a physical constant, approximately equal to the most probable distance between the nucleus and the electron in a hydrogen atom in its ground state.
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