question_answer 141)

  Why was a change in the Bohr's Model of atom required? Due to which important development(s), concept of movement of an electron in an orbit was replaced by the concept of probability of finding electron in an orbital? What is the name given to the changed model of atom?  

Answer:

  Influence of uncertainty principle on Bohr?s model of the atom: On the basis of this principle, Bohr's picture of an electron in an atom, which gives a fixed position in a fixed orbit and definite velocity to an electron, is no longer tenable, The best we can think is in terms of probability of locating an electron with a probable velocity in a given region of space at a given time. The space or a three-dimensional region around the nucleus where there is maximum probability of finding an electron of a specific energy is called an atomic orbital. Heisenberg's uncertainty principle replaced the concept of orbit by orbital because both position and momentum can be calculated in the orbit of electron, which is impossible. The new changed model of atom was called wave mechanical model of atom.