What is the Thomson's, Rutherford's & Bohr's Atomic Model theory?

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We can explain, atom structure from these atomic model theories
(1) Thomson's Atomic Model - J.J.Thomson gave the first idea regarding structure of atom. According to this model.
• An atom is a solid sphere in which entire & positive charge. It's mass is uniformly distributed in which negative charge (electron) are embedded like seeds in watermelon.
 • This model explained successfully the phenomenon of thermionic emission, ionisation & photoelectric emission.

Failure of Thomson's Atomic Model -  
• Thomson's atomic model fail to explain the scattering of alfa - particles & it can't explain the origin of spectral lines observed in the spectrum of hydrogen & other atom.

(2) Rutherford's Atomic Model - Rutherford's atomic  model bassed on alfa - particles scattering experiment.
• Most of the mass & all of the charge af on atom concentrated in a very small region is called atomic nucleus.
• Nucleus is positively charged & it's size is 10—¹⁵m =1Fermi.
• All the protons & neutrons are present in the nucleus. In an atom number of protons is equal to the number of electrons.
• In an atom there is maximum empty space & the electrons revolve around the nucleus in the same way as the planet revolve around the sun.

Failure of Rutherford's Model - 
• According to electrodynamics theory, an accelerated charged particle should continuously rediate energy. But Rutherford's model couldn't explain stability of atom because, an electron in an circular path around the nucleus should radiate energy, then it's circular orbit will becomes smaller & it should ultimately fail inside nucleus.
• This model don't explain the line spectrum of atom.

(2) Bohr's Atomic Model - Niels Bohr  proposed the bohr model of the atom in 1915. Bohr's model is a modification of the earlier Rutherford's model.The Bohr's model is based on quantum mechanics.
• The atom consists of small nucleus (positively charged) & electrons(negative charged) surrounded moving around the nucleus in orbits.
• In an atom, electrons revolve around the nucleus in a definite circular path called shells or orbits.
• Each shell or orbits has a fixed energy & these circular orbits are know as orbital shells.
 • The energy levels are represented by an integer(n=1,2,3,4,_ _ _) known as the quantum number. The range of quantum number starts from nucleus side with n=1 having the lowest energy level. The orbits n=1,2,3,4,_ _ are assigned as K,L,M,N shells.
• Angular momentum of an electron in an orbit.
Where, m = mass of the electron
              v = trangential velocity of the revolving electron
              r = radius of the orbit
             h = Plank's constant
             n = Any 
• Electrons can only gain & lose energy bby jumping from one allowed orbit to another, observing or emitting electromagnetic radiation determined by the energy difference of the levels. 
    Planck Relation 
Where,E = Energy
            n = Planck constant
            v = Frequency
            c = Speed of light
       
Failure of Bohr's Model - 
• It doesn't explain the Zeeman effect(effect of magnetic field on the spectrum of atom).
• It also failed bro explain the stark effect(effect of electric field on the spectrum of atom).
• It violates the Heisenberg uncertainty principle because it considers electrons to have both a known radius & orbit.
                

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