# Bohr Atom

**Bohr’s Postulates or Bohr’s Model of the Hydrogen Atom!**

Students will understand Bohr’s experimental design and conclusions that lead to the development of his model of the atom, as well as the limitations of his model. ADVERTISEMENTS: Bohr’s Postulates or Bohr’s Model of the Hydrogen Atom! An atom has a number of stable orbits in which an electron can reside without the emission of radiant energy. Each orbit corresponds, to a certain energy level. ADVERTISEMENTS: 2. An electron may jump spontaneously from one orbit (energy level E1) to the other. Bohr agreed with Rutherford’s proposal that in the atom the electrons revolve around a central positively charged nucleus that is responsible for most of the weight of the atom. But from his special evidence, he concluded that electrons are found at only certain distances from the nucleus, and have particular values of energy. Atom - Atom - Bohr’s shell model: In 1913 Bohr proposed his quantized shell model of the atom (see Bohr atomic model) to explain how electrons can have stable orbits around the nucleus. The motion of the electrons in the Rutherford model was unstable because, according to classical mechanics and electromagnetic theory, any charged particle moving on a curved path emits electromagnetic.

In 1913 Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. The motion of the electrons in the Rutherford model was unstable because, according to classical mechanics and electromagnetic theory, any charged particle.

1. An atom has a number of stable orbits in which an electron can reside without the emission of radiant energy. Each orbit corresponds, to a certain energy level.

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2. An electron may jump spontaneously from one orbit (energy level E_{1}) to the other orbit (energy level E_{2}) (E_{2 }> E_{1}); then the energy change AE in the electron jump is given by Planck’s equation

### Bohr Atomic Theory Model

∆E = E_{2}-E_{1} = hv

Where h = Planck’s constant.

### Bohr Atom Date

And v = frequency of light emitted.

3. The motion of an electron in a circular orbit is restricted in such a manner that its angular momentum is an integral multiple of h/2π, Thus

mvr = nh/2π, where m = mass of the electron

v = velocity of the electron

r = radius of the orbit an

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n = an integer called principal quantum number of the electron.

4. A special surface around nucleus which contained orbits of equal energy and radius was called shell. These shells are numbered from inside to outwards as 1, 2, 3, 4 etc. and called K, L, M, N etc., respectively.