Monday, August 3, 2009

What does an atom look like?

rutherford's atom, and that of Bohr's does not satisfy experiments. the QM model says that we can only talk of probability of finding an electron at a perticular place.
the electron is in a state described by 4 quantum numbers.

One must imagine a statistical distribution of electrons only.

And a statistical distribution, should give a cloudy kind of perception, where the probablity of of finding the electron is more where the density of this cloud is more...

one thing that i would like to add in above discussion is that.
if u imagine a single atom then probability of finding an electron in infinity is there. but we take radius of atom as 90% probability of finding electron near to nucleus away from that we neglect it.

if electrons are statistically distributed, then why dont they fall towards the nucelus.
if they dont move, they shall fall, if they do, then also they shall fall(by losing enrgy)
tell me if the electrons are moving or not

Electrons in atoms have discrete levels of energy, that's why "they don't fall" (in quotes because you can't really talk about the trajectory of an electron).

And for some orbitals there is a non-zero probability of the electron to be inside the nucleus, and that is responsable, for instance, for the hyperfine splitting.

The hyperfine splitting in the hydrogen spectra has important applications in astrophysics: Tully and Fisher used the broadening of this absorption line to measure the rotation velocity of galaxies, and hence its mass, that are too far away to be measured by primary distance indicators.

It's also widely used in atomic clocks... I think, but I may be wrong, that the most modern definition of the second uses an hyperfine transition of the cesium-133.

People also use t to separate isotopes and a bunch of other stuff that I have no idea. The important message is that it's important, in some sense, the fact that the electron can be inside the nucleus with non-zero probability.

You simply can't think in classical terms, that's where your doubt comes from.

The electrons don't fall into nucleus due to uncertainty principle.The uncertainty principle forces every system to a minimum level.No energy level below the ground state exists

which is right answer?

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