# Bohr Radius

- The distance corresponding the mean distance of an electron from the nucleus in the ground state of the hydrogen atom.
- a
_{0}= 5.291772x10^{-11}m

- The Bohr model of atoms states:
- An electron moves around the nucleus in a circular orbit under the influence of the electrostatic attraction between the electron and the nucleus.
- The orbit of an electron can only be a multiple of
*h*/2*π*, where*h*is Planck's Constant. - The total energy of an electron,
*E*, remains constant as the electron does not radiate electromagnetic energy. - When an electron moves from an orbit with energy
*E*to an orbit with lower energy_{i}*E*, electromagnetic radiation is emitted. The frequency of this elecromagnetic radiation is given by_{f}

- where
*ν*= frequency of the elecromagnetic radiation [Hz]*E*,_{i}*E*= energy of electron in orbits_{f}*i*,*f*[J]*h*= Planck′s constant [Js]

**See also: **Bohr Atom, Physical Constants.

**Subjects: ** Physics