Why do electrons orbit the nucleus

An electron will only react with a proton in the nucleus via electron capture if there are too many protons in the nucleus. When there are too many protons, some of the outer protons are loosely bound and more free to react with the electron. But most atoms do not have too many protons, so there is nothing for the electron to interact with. As a result, each electron in a stable atom remains in its spread-out wavefunction shape.

Each electron continues to flow in, out, and around the nucleus without finding anything in the nucleus to interact with that would collapse it down inside the nucleus. It's a good thing too, because if electron capture was more common, matter would not be stable but would collapse down to a handful of nuclei. Topics: atom , atoms , collapse , decay , electron , electron capture , electrons , nucleus , quantum , wavefunction , wavefunction collapse.

The total kinetic energy of the entire string averaged over time is zero, since the overall string is not going anywhere with respect to the guitar.

But the kinetic energy of any small part of the string at a given moment is not zero. In this way, a plucked guitar string experiences local motion but not overall motion.

An electron in an atomic orbital state acts somewhat like a plucked guitar string. It is spread out in a three-dimensional cloud-like wavefunction that vibrates. Whereas a guitar string vibrates up and down, an atomic electron wavefunction simply vibrates strong and weak.

The frequency at which the electron wavefunction vibrates is directly proportional to the total energy of the electron. Electrons in higher-energy atomic states vibrate more quickly.

Because an electron is a quantum object with wave-like properties, it must always be vibrating at some frequency.

In order for an electron to stop vibrating and therefore have a frequency of zero, it must be destroyed. In an atom, this happens when an electron is sucked into the nucleus and takes part in a nuclear reaction known as electron capture.

With all of this in mind, an electron in a stable atomic state does not move in the sense of a solid little ball zipping around in circles like how the planets orbit the sun, since the electron is spread out in a wave. Furthermore, an electron in a stable atomic state does not move in the sense of waving through space. The orbital electron does move in the sense of vibrating in time.

But the truth is more complicated than this simple picture depicts. There are two things that describe the electron in quantum theory: the electron's quantum wavefunction, and the magnitude squared of the electron's quantum wavefunction.

This is just the curve labeled "probability density"; its steep climb as we approach the nucleus shows unambiguously that the electron is most likely to be found in the tiny volume element at the nucleus. But wait! Did we not just say that this does not happen? This yields the curve you have probably seen elsewhere, known as the radial probability , that is shown on the right side of the above diagram.

To sum up, the probability density and radial probability plots express two different things: the first shows the electron density at any single point in the atom, while the second, which is generally more useful to us, tells us the the relative electron density summed over all points on a circle of given radius.

Chem1 Virtual Textbook. Quantum theory to the Rescue! The Battle of the Infinities Saves the electron from its death spiral As you know, the potential energy of an electron becomes more negative as it moves toward the attractive field of the nucleus; in fact, it approaches negative infinity. Probability Density vs. I hope the above takes care of your first and last question which were: Could you please tell me if electrons ever " fall " into the nucleus of an atom?

Let me make a comment on the next question. You wrote: I have never read of this happening - not even in the depths of space where the temperature is so cold the electrons should be moving very slowly and hence should "fall" in. This energy level is called the ground state.

So, even if atoms are in a very very called environment, QM prohibits electrons from falling to the nucleus. The worst it can happen, is that they will sit in their ground states. Finally we get to your last question: If the electron of a hydrogen atom were to " fall " into the nucleus then this would produce a proton.

It is possible to force electrons into the nucleus. You have to overcome certain energy barriers made by other, possibly present electrons the repulsive force between these electrons makes this barrier. Once you do that, electrons can enter the nucleus and can react with protons or neutrons, but that is another story. It is not anymore QM which is responsible for description of such an event, but something called the Standard Model of Particle Physics.

This is the model we are verifying here at Fermilab. And of course, at the same time we are looking for the ultimate theory of our universe. I hope your questions got answered. If not, please do not hesitate to write us and we will try to do our best.