Why doesn't electrons merge into the nucleus of an atom...?

do sattelites fall onto the earth?.....No, they are kept there with help of centrifugal force. similarly electrons in an atom. If electrons merge into nucleus, how can we exist?....nothing will be present in universe, except neutrons!

Rutherford could not explain why electrons do not fall into the nucleus because of the opposite charges. This fact would have occurred because of the Electromagnetic Theory of quantum physics, which states that any body under centripetal acceleration radiates energy. With decreasing energy, the electron would ultimately lose its velocity and hence fall into the atomic nucleus.

Neils Bohr postulated that electrons follow certain special orbits known as discrete orbits, whose structure is such that energy is not radiated even under centripetal acceleration. Hence, electrons maintain their speed and do not cease to the magnetic attraction of the nucleus.

Bohr's model roughly explains this for the same reason that the moon doesn't crash in to Earth...sufficient tangential speed. NOT "the centrifugal force", since that isn't a force...but more rather, it is FALLING (due to electrostatics rather than gravity) and overshooting its target continuously.

It turns out that the above is an oversimplified model for the atom by today's standards. The real reason is that electron energy is quantized, and it simply isn't an acceptable condition for the electron to do so. Another explanation is the Pauli Exclusion Principle, whereby no two particles are allowed to occupy the same quantum state.

In some extreme scenarios, the electrons do collapse to the nucleus. We call the resulting body...a neutron star.

Rutherford couldn't, but Niels Bohr made the first steps towards answering this problem. Electrons don't spiral into the nucleus because energy is quantised. Electrons can only occupy certain energy levels in an atom, not continuously lose energy and spiral inwards. Because electrons cannot simply radiate energy, there is a point at which they are set in their orbitals and cannot approach closer without violating quantum physics.

Neils bohr suggested that electrons revolve around the nucleus in certain special orbits and each of these orbits has different energy levels associated known as energy shells and they do not collapse into the nucleus.

Check this out ...

http://chemistry.about.com/od/atomicstructure/a/bo...