2
$\begingroup$

Does an electron possess potential energy while revolving around a nucleus ?

I guess that it wont. Why because when an energy is given it converts into its kinetic energy so that it revolves around a nucleus in a higher orbit .

$\endgroup$
  • 1
    $\begingroup$ Please note that an electron is a quantum mechanical entity as well as the nucleus. The solution of the quantum mechanical problem gives orbitals for the electrons, probability loci, not orbits . en.wikipedia.org/wiki/Atomic_orbital $\endgroup$ – anna v Nov 19 '14 at 12:36
  • $\begingroup$ @annav Does it possess only kinetic energy ? I need a clear definition $\endgroup$ – Vinayak Nov 19 '14 at 12:38
  • 2
    $\begingroup$ Vinayak, inspect the Hamiltonian (total energy operator) for the Hydrogen atom. Is there only a kinetic energy term? $\endgroup$ – Alfred Centauri Nov 19 '14 at 12:45
  • $\begingroup$ Depending on the asker's level of education, @Alfred's comment was not very helpful, but be expanded into a valid answer. $\endgroup$ – M.Herzkamp Nov 19 '14 at 13:10
  • $\begingroup$ "revolving around"-What do you mean by revolving? are you saying it to be continuous path? Discussion: chat.stackexchange.com/rooms/17149/did-you-read-this-book $\endgroup$ – Immortal Player Nov 19 '14 at 15:09
2
$\begingroup$

Does an electron possess potential energy while revolving around a nucleus ?

Here are Hydrogen atom energy levels given in the language of the Bohr atom

hydrogen energy levels

This is the image you have in mind while asking your question. The ev on the side show how much energy the electron lost falling in the potential well of the proton.

The Bohr atom was a useful model and is still shown because the solutions are the same in this primitive precursor of the quantum mechanical equations that need to be solved . Quantum mechanics is a theory from which the microcosm can be modeled , whereas the Bohr model was an ad hoc model that described the spectrum of the hydrogen atom.

The difference lies that though the electron has a definite energy in the ground state, (n=1 in the plot) and has given up potential energy by falling down to it ( in the form of a photon seen in the spectral lines of Hydrogen) the wave referred in the figure ( wavelength given) has nothing to do with planetary like orbits.

The hydrogen atom is described by a wavefunction, and the square of the wavefunction gives the probability distribution for the location of the electron, not a function as with moon and planets around the earth. This locus of probability is called an orbital and has different shapes for different energy level angular momenta.

atomic orbitals

The shapes of the first five atomic orbitals: 1s, 2s, 2px, 2py, and 2pz. The colors show the wave function phase. These are graphs of ψ(x, y, z) functions which depend on the coordinates of one electron.

The squares of these wavefunction representations give the probability of finding an electron with specific variables if an interaction/ experiment is performed.

Thus even if we can name the energy of the probability cloud as "kinetic" it does not have the classical meaning except as an average tag.

Generally, the electron before falling into the attraction of the proton has potential energy , similar to a ball high up has potential energy before hitting the ground. When trapped by the potential it releases the energy in the form of a photon, whose energy will depend on which energy level the electron lands. When caught in a higher orbital it will still have some potential energy until it falls to the ground state by photon emission.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.