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Guidance with some chemistry concepts

  1. Nov 14, 2014 #1
    Hello! I understand that a lot of this may be considered physics, but It is for AP Chemistry.

    We will likely be required to identify a certain element on the periodic table given a set of quantum numbers of one of its electrons. I understand the primary quantum number, n, essentially corresponds to the rows on the table. L dictates the type of orbital (s, p, d, etc.). But I am confused on how I can further narrow it down using magnetic quantum number (m) and spin number.

    For example, I know n=2, l=0 would be either Lithium or Beryllium. What would be the m / spin numbers for each? Essentially, we are being asked to pinpoint a certain element on the table given 4 quantum numbers. I understand how to narrow it down using the primary quantum number and angular quantum number but do not understand how I can further narrow it down using magnetic quantum number and spin number.

    Sorry if that question is a little discombobulated, hopefully it makes sense.

    My other concern is the uncertainty principle. How are we meant to do calculations using the uncertainty principle?
     
  2. jcsd
  3. Nov 14, 2014 #2

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    Tain't too "discombobulated" to understand your concern. You will have to be given additional information about the electron for which quantum numbers are given, whether the atom is in its ground state, and possibly more; for instance, "n=2, l=0" covers everything from excited H (or He) through the transuranics. Presumably you'll be told it's the highest energy electron in a ground state atom, and judging from your presentation of the question you won't have much trouble. Transition metals and lanthanides might get a little weird depending on how much cribbing material you're allowed.

    Uncertainty? What sort of calculations are you being asked/expected to handle?
     
  4. Nov 15, 2014 #3
    Yes - I think that's correct. We are going to be expected to pinpoint the highest energy electron in the ground state atom, and we'll have to identify what element that would be based on a set of 4 numbers. However, I'm not sure how I can use the 3rd and 4th numbers to identify what element we are talking about.

    As for uncertainty, the "delta" for each X and MV mean uncertainty, not change, like delta normally means, correct? I don't actually need the value for mass or velocity itself to solve for the other, only its uncertainty?
     
  5. Nov 15, 2014 #4

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    If you're given a set of quantum numbers, you have been given the order in which the quantum levels are filled, have you not, and can then count electrons.

    "Δ" indicates uncertainty, yes, and those uncertainties are the values you use.
     
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