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Which pair of elements is most apt to form an ionic compound

  1. Oct 15, 2007 #1
    which pair of elements is most apt to form an ionic compound with each other? nitrogen and hydrogen or barium and bromine?

    please explain
     
  2. jcsd
  3. Oct 16, 2007 #2
    one way to look at it involves electronegativity. For a bond to be ionic, difference in electronegativity should be greater than 1.7

    electronegativity of N is 3.0, and that of hydrogen is 2.2
    the difference is less than 1.7

    electronegativity of barium is 0.89 and that of bromine is 2.96
    the difference is more than 1.7, hence ionic.

    more logically, the bond will depend on polarisation. This occurs when a high charge density cation distorts the electron cloud of a large anion. When polarisation occurs, there is sharing of electrons instead of transfer of electrons, hence a covalent bond.
     
  4. Oct 19, 2007 #3
    While only looking at electronegativity, other trends come into play as well.
    Bromine is atomic number 35, and Barium is 4.
    Hydrogen is 1, and Nitrogen is 7. The valence shells around the hydrogen and nitrogen are a lot lesser. Hydrogen bonding is a very strong force. Despite the electronegativities, I believe that the Hydrogen and Nitrogen will be more apt to for an ionic compound.
    (Don't count on me though, I'm only 16 and recently started AP Chem.
     
  5. Oct 19, 2007 #4
    hydrogen bonding is an INTERMOLECULAR FORCE (even if we call it H-bond), it occurs between molecules, such as water or ammonia. it is in no way an actual bond.

    actually electronegativity sums the atomic size. The fatter the atom, the smaller is the electronegativity and vice versa.
     
  6. Oct 19, 2007 #5
    very good answers thank you everyone
     
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