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Polarity in water molecule and electronegativity of oxygen in that molecule.

  1. Jun 17, 2012 #1
    H20 is polar in nature.
    It is fundamentally because oxygen is more electronegative than hydrogen and the shared electrons tend to be near oxygen.
    This may be because the atomic number of oxygen is more than that of hydrogen.
    But in the bond I don't understand how the 2 shared electrons experience more force from the oxygen side than they do from the hydrogen side.
    As the 2 electrons are experiencing the force of 2 protons from both the sides.
    Are you getting it, what I am trying to convey?
  2. jcsd
  3. Jun 18, 2012 #2
    Oxygen has more than 1 proton. Because of this, the nucleus of oxygen has a greater affinity for electrons than hydrogen.
  4. Jun 21, 2012 #3
    It is to do with ionization energies. When you go from left to right (and up) you encounter smaller atoms. Which means that the proximity of their electrons is a lot closer than a larger atom. Due to the fact that the Oxygen electrons are a lot closer to the nucleus of the atom a higher amount of energy is required to pull them apart. :) Hope this helped
  5. Jun 21, 2012 #4
    Also, as Matt states, the oxygen is closer to each hydrogen atom than each hydrogen atom is to each other. Each OH bond in H2O is ≈95.84 pm. The bond angle is 104.45°, making the hydrogen atoms 177.38 pm apart.
  6. Jun 22, 2012 #5
    Why? This I am not able to understand.
  7. Jun 22, 2012 #6
    Well, most of an atom's size is taken up by it's electron cloud. Having more protons means wanting more electrons. Oxygen's atomic number is 8, so it has 8 protons and 8 electrons in ground state. Hydrogen only has 1 proton, so it only has 1 electron. And more electrons means a larger atom.
  8. Jun 22, 2012 #7
    why closer?
  9. Jun 24, 2012 #8
    In short, so it doesn't get too confusing:

    500px-Electron_shell_001_Hydrogen.svg.png 500px-Electron_shell_008_Oxygen.svg.png
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