Chemistry
State in brief the drawbacks of Rutherford's atomic model correlating them with the postulates of Bohr's atomic model.
Answer
Drawbacks of Rutherford's Atomic Model :
- In Rutherford's model of the atom - the electrons revolve around the nucleus and the attractive force of the positively charged nucleus would be balanced by the centrifugal force arising due to the rotation of electron.
- If an electron moves round the nucleus - it must radiate out energy and gradually move towards the nucleus following a spiral path - till it collides and ultimately collapses in it.
- Thus, Rutherford's model could not explain correctly the stability of an atom.
Postulates of Bohr's Atomic Model :
- Electrons revolve around the nucleus in fixed orbits or energy levels, possessing certain amount of energy.
- The integer n represents the various energy levels 1, 2, 3 or K, L, M starting from the innermost.
- As long as the electrons rotates in one of the energy levels - it neither loses or absorbs energy. When energy is supplied initially to the atoms - an electron moves to an orbit of higher energy. When this electron drops back to the original orbit - energy is radiated by the atom - according to equation E2 - E1 = hγ
[E2 and E1 are energy states of the electron in higher and lower orbit.]
Bohr's model gave the preciseness of location and mode of rotation of electron around the nucleus.
Related Questions
State the main postulates of Dalton's atomic theory. How does the modern atomic theory contradict and correlate with Dalton's atomic theory.
Explain in brief the experimental proofs which led to the discovery of –
(i) Electrons
(ii) Protons
(iii) atomic nucleus
(iv) neutrons.
Represent each of the following :
(i) a proton 'p'
(ii) an electron 'e'
(iii) a neutron 'n'
in terms of it's symbols showing the subscript and superscript values.
What is meant by the terms :
(i) subatomic particles,
(ii) nucleus,
(iii) orbits,
(iv) atomic number
(v) mass number with reference to an atom.