# Heisenberg Uncertainty Principal with regards to electron orbits

1. Sep 15, 2008

### ajassat

Hello all,

I have gathered that the orbit of an electron cannot be calculated due to the uncertainty principal which states that position becomes uncertain when momentum is measured and vice versa.

From this I understand that an orbit is not possible for an electron, hence the term 'orbital'.

If the above is the equation for the Heisenberg Uncertainty principal, how would I use it in order to show that an electron orbit is impossible?

2. Sep 16, 2008

### olgranpappy

in order to have a well defined orbit you need to have $\Delta x$ much less than the size of the atom (the position of the electron in its "orbit", x) *and* you need to have $\Delta p$ much less than the momentum of the electron in its "orbit", p. These to requirements are incompatable because of the uncertainty principle. I.e., if I force $\Delta x$ to be much smaller than x then I find that $\Delta p$ is much *larger* (not much smaller) than p.

Last edited: Sep 16, 2008
3. Sep 20, 2008

### ajassat

Thanks for this reply. It has made things a lot clearer. Is there any chance of using numbers too so I can really get a grip on it?