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How to say whether an element is more electronegative?

  1. Feb 22, 2016 #1
    Amoung phosphorous and nitrogen which one is more electronegative? My book says it is nitrogen because it is small in size but shouldn't it be phosphorous since it has higher valency than nitrogen?
    When we compare two elements based on their electronegativity, should we not look at it's valencies? If not what is the criteria to be used?
    Finals coming up,answer soon,please!
     
  2. jcsd
  3. Feb 22, 2016 #2

    BvU

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    Both N and P have 5 electrons in the outer shell, so the deciding factor is size.
     
  4. Feb 22, 2016 #3
    I just found out another factor too.N has 2 shells while P has 3 shells.Now it is known that as we go down a group electronegativity decreases.Hence N should be more electronegative since it is place before phosphorous in 5th group depending on their shells.
     
  5. Feb 22, 2016 #4

    BvU

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    Yes, there is some correlation between effective size and number of shells ...
     
  6. Feb 22, 2016 #5

    Borek

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    Electronegativity - while sometimes quite useful - is a rather handwavy concept, poorly defined (many definitions, sometimes giving contradicting predictions). As with every poorly defined concept it becomes hard to apply/explain/use when you get into details.

    - Doc, it hurts when I do that.
    - Don't.

    That how I approach this kind of problems :wink:
     
  7. Feb 22, 2016 #6

    BvU

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    Borek is right: look further down in these tables -- P, As, Sb, Bi
     
  8. Mar 3, 2016 #7
    Nitrogen is smaller, and so has higher charge density. Also the nucleus is less shielded so electrons will feel a greater pull, which explains it's higher electronegativity.
     
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