1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Why does an electron not stick to the nucleus?

  1. Dec 17, 2014 #1
    If the electrons are negative charged and nucleus is positively charged, then why do electrons still orbit around the nucleus at a distance and not just stick to the nucleus?
  2. jcsd
  3. Dec 17, 2014 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The Bohr atom and little tiny charged marbles "orbiting" one another like a miniature solar system is NOT a reflection of what is actually happening; it WAS a model that was used well over a century ago to investigate certain initial hypotheses of the mechanics of very small systems. The current quantum mechanical model of interactions of electrons with atomic nuclei gives you ONLY the probability of finding an electron at a certain distance "r" in a certain direction θ, φ from the nucleus. It does not describe an orbital trajectory.
  4. Dec 18, 2014 #3
    But why does the electron stay at a distance away from the nucleus instead of sticking?
  5. Dec 18, 2014 #4


    Staff: Mentor

    It is due to the uncertainty principle. If the electron is stuck to the nucleus then the uncertainty in its position is very small so the uncertainty in its momentum is very large. This in turn means that the average kinetic energy is high. Since an atom likes to be in a low-energy state it will give off energy to go to a state where the position is more uncertain and the momentum less uncertain.
  6. Dec 18, 2014 #5


    User Avatar

    Staff: Mentor

    In fact, an atomic electron generally does have a small probability of being located inside the nucleus (very small distance r from the center of the atom/nucleus). In certain isotopes, this produces a type of nuclear decay called electron capture.

  7. Dec 19, 2014 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    This is a good time to introduce to you, if you haven't discover it already, the https://www.physicsforums.com/forums/physics-faq.209/ [Broken], and https://www.physicsforums.com/threads/why-dont-electrons-crash-into-the-nucleus-in-atoms.511179/ [Broken] in particular.

    Last edited by a moderator: May 7, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook