Define bohr model and its postulates..........
Answers
Bohr's atomic model is the modified one of rutherford's atomic model and here are his postulates:
☆In an atom,electrons revolve around a nucleus in stationar circular orbit.
these paths are called orbit or shell
☆As long as the electron is in the same orbit,it doesn't lose or gain energy
☆The circular orbit are numbered as 1,2,3 and 4 or designated as k,l ,m,n shells.
These numbers are reffered to as principal quantum number
☆As we move away from the nucleus, the energy of the orbit constantly increases
☆Maximum number of electrons that can accommodate in a energy level is 2n2
☆when a electrons jump from higher to lower energy enegy level, it gives off
energy.
☆When a electrons jump from lower to higher energy level,it gains electron.
The Bohr's postulates -
1) An electron can revolve around the nucleus in certain fixed orbits of definite energy without emission of any radiant energy. Such orbits are called stationary orbits.
2) An electron can make a transition from a stationary state of higher energy E2 to a state of lower energy E1 and in doing so, it emits a single photon of frequency,
ν=E2−E1h where h is the Planck's constant.
Conversely, on absorbing an energy, E2−E1when the electron is at energy E1, the electron can make a transition from E1 to E2.
3) Only those orbits are allowed for which the angular momentum of the electron is an integral multiple of h2π,
Thus, L=nh2π where n=0,1,2,
postulates of Bohr's atomic model : According to Bohr's theory , electrons revolve in definite circular orbits around the nucleus and these orbits are designated by the letters K, L, M, N or by the numbers 1, 2 ,3, 4 and so on. ... It explains the stability of an atom and also the line spectrum of hydrogen atom.
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