Question about electrons moving from ground state

  1. Ok, I am currently taking chemistry, and the course involves some aspects of quantum physiscs, such as bohr models, quarks, and orbitals. My teacher taught us that when the elcetrons become excited they move up an energy level. However they do not move in the traditional sense, "they are here, and than they are there." He does not know much more about the topic, seeing as he is a chemistry teacher and not physics. Could somebody please clear up how the electron "teleports" between the energy levels and how we know that it is the same electron.

    Thank you for your time.
  2. jcsd
  3. Integral

    Integral 7,288
    Staff Emeritus
    Science Advisor
    Gold Member

    It helps if you drop the notion of an electron as a small localized ball. Consider the electron as a probabliity distribution. We cannot specify its location at any given time, only the probability that it will be found in a region. When an electron is excited to a higher energy level, its probability distribution shifts, it is now more likely to be found in the higher level. There does exist a finite probability that it could be in the lower energy level, or on Jupiter. It is all a matter of probability.
  4. Also: You never know which electron you're looking at. All electrons are identical. Suppose you have only two of them. You cannot put a tag on one of them and follow it around. After a short time they might have interchanged (or not) without you ever noticing.
    As integral said it is al probability.
    The only difference between two energy levels is the form of the probability distribution. In an atom for instance the groundstate is a sphere centered around the nucleus, while the frist excited state sort of looks like an 8 with zero probability at the nucleus.

    Bohr did not say: "He who claims to fully understand Quantum Mechanics, does not understand a single bit of it" for nothing.

    Good luck in your studies
  5. Njorl

    Njorl 818
    Science Advisor

    Think of the electron as a dog you lost. In the ground state, he is your tired old dog. He probably hasn't gone far. If a poodle in heat walks by, he becomes excited. In an excited state, it is much more likely that he could be farther away. In either case, he might be in Pittsburgh, or he might be in the crawlspace under your house, but until you find him, you can only talk about probabilities.

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