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I find myself doubting myself. - Chemistry

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    The principle quantum number:

    Lowest energy electron of Krypton, it's quantum number would be 1, surely?
    Highest energy of lithium would be 2?

    Gah I hate doubting myself like this.
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    (Original post by KyleH123)
    The principle quantum number:

    Lowest energy electron of Krypton, it's quantum number would be 1, surely?
    Highest energy of lithium would be 2?

    Gah I hate doubting myself like this.
    Yes
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    (Original post by GradeA*UnderA)
    Yes
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    (Original post by KyleH123)
    Hero
    Principle quantum number is essentially a term for the number of energy levels/shells in an atom. Krypton has a quantum number 4 (as it has 4 energy levels) while lithium has a quantum number of 2.
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    (Original post by GradeA*UnderA)
    Principle quantum number is essentially a term for the number of energy levels/shells in an atom. Krypton has a quantum number 4 (as it has 4 energy levels) while lithium has a quantum number of 2.
    Yeah. Thanks a lot! :-)
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    (Original post by GradeA*UnderA)
    Principle quantum number is essentially a term for the number of energy levels/shells in an atom. Krypton has a quantum number 4 (as it has 4 energy levels) while lithium has a quantum number of 2.
    Not quite ..

    The principle quantum number is the number of the energy level under discussion.

    Krypton has four shells, each with a different principle quantum number.

    You consider the position of an electron. It can be described by four quantum numbers, n, m, l & s

    n = the energy level
    m = the sub-shell
    l = the azimuthal (magnetic orientation of the orbital)
    s = the spin
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    (Original post by charco)
    Not quite ..

    The principle quantum number is the number of the energy level under discussion.

    Krypton has four shells, each with a different principle quantum number.

    You consider the position of an electron. It can be described by four quantum numbers, n, m, l & s

    n = the energy level
    m = the sub-shell
    l = the azimuthal (magnetic orientation of the orbital)
    s = the spin
    God damn Charco, this is AS for crying out loud
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    (Original post by GradeA*UnderA)
    God damn Charco, this is AS for crying out loud
    :getmecoat:
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    (Original post by charco)
    :getmecoat:
    (Original post by GradeA*UnderA)
    God damn Charco, this is AS for crying out loud
    Hey guys. I was under the impression that the groups go like
    Lithium Group 1 eg
    Magnesium group 2, eg
    and then everything inbetween group 2 and Boron is also group 2?

    I think I'm wrong about this.
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    (Original post by KyleH123)
    Hey guys. I was under the impression that the groups go like
    Lithium Group 1 eg
    Magnesium group 2, eg
    and then everything inbetween group 2 and Boron is also group 2?

    I think I'm wrong about this.
    First two are correct, last line is wrong. Okay, we know that in group 1, there is Li and Na and that group 2 there is Mg and Ca. The "real" group 3 is the one containing scandium and yttrium, however, at A Level, we assume that the group that contains boron and aluminium is group 3(this group is called group 13 to account for the d block groups). So those elements in between group 2 and group 3 aren't group 2, but it doesn't matter for AS. You just have to be able to notice trends, write electron structures for them and know common ions, eg Fe2+, Fe2+, Cu2+ etc.
 
 
 
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