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Homework Help: Electron Configuration

  1. Nov 5, 2005 #1
    Which of the following three sets consist of atoms or ions with the same electron configuration in the ground state?
    I. O (2-), Ne, and Mg (2+)
    II. Ni, Cu+, Zn 2+
    III. Hg, Tl+, and Pb (2+)
    a. all but (II)
    b. all but (I)
    c. all three sets
    d. only (I)
    Is it all but ii. because Cu loses its 4s shell?
    Last edited: Nov 5, 2005
  2. jcsd
  3. Nov 5, 2005 #2
    Aka isoelectronic series

    Well O2-, Ne, and Mg2+ all have the configuration of [Ne]

    and for 2 Ni is [Ar] 3d8 4s2
    and Zn is [Ar] 3d10 4s2
    Zn+2 would then be [Ar] 3d10 because you take from the outermost shell
    Cu is [Ar] 3d10 4s1 so Cu+ would be [Ar] 3d10

    So 2 isn't isoelectronic

    For #3, Hg is [Xe] 4f14 5d10 6s2
    Tl is [Xe] 4f14 5d10 6s2 6p1 so Tl+ is indeed [Xe] 4f14 5d10 6s2
    Pb is [Xe] 4f14 5d10 6s2 6p2 so Pb+2 is indeed [Xe] 4f14 5d10 6s2

    So you are indeed correct but your explanation doesn't quite make sense to me.
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