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How to determine the value of electronegativity

  1. Aug 24, 2011 #1
    for an atom that is an element in Period 4 , Group 7

    to compare with another atom of element in Period 3, Group 5

    Without looking at the Periodic table or electronegativity values, how can I

    determine which one of these two atom is more electronegative?

    (While Period 4, Group 7 has more number of outermost electrons but it has a larger atomic radius)

    Can anyone good at Chemistry explain? Thank you very much!
  2. jcsd
  3. Aug 25, 2011 #2
    Well period 4 elements will be way bigger than period 3 elements and as a result their effective nuclear charge is a lot weaker because their nuclei are shielded way more (due to the greater number of electrons surrounding the nuclei). Thats why electronegativity usually decreases as you move down periods. Group 5 and 7 are d block metals and they start at period 4 so you're question doesn't make sense. Lets say its period 4 and 5 instead of 3 and 4. Electronegativity trends get a bit abnormal in the d block and it often increases as you move down periods. I don't know why that is.
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