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electronegativity Watch

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    Hi can anyone tell me what is meant by:

    The explanation is that silver chloride actually has a significant amount of covalent bonding between the silver and the chlorine,

    because there isn't enough electronegativity difference between the two to allow for complete transfer of an electron from the silver to the chlorine.


    thanks
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    Electronegativity of Silver = 1.93. Electronegativity of Chlorine = 3.16.

    3.16 - 1.93 = 1.23

    Here are some of the rules I found browsing around defining "Ionic vs Covalent" bonds:

    if ΔEN ≤0.5, the compound is NON polar covalent
    if 0.5 < ΔEN ≤ 1.5, the compound is POLAR covalent
    if 1.5 < ΔEN ≤ 2.0 AND the compound contains NO metals, it is polar covalent
    if 1.5 < ΔEN ≤ 2.0 AND the compound contains a metal, it is IONIC
    if 2.0 < ΔEN, the compound is ionic.

    [From here on, I'm gonna shorten "Electronegativity" down to "EN"

    Electronegativity is how strong an atom's affinity for electrons is. A higher electronegativity is a higher affinity. If two atoms share very close EN values, then the electrons will be shared roughly the same between the two.

    By this definition above, AgCl seems to be under the "polar covalent" section, whereby the electrons are very strongly pulled in towards the chlorine atoms without complete dissasociation.

    Basically, very few bonds are purely ionic or purely covalent. Imagine they are on a scale between the two extremes. Even HCl, a covalent molecule, contains 90% ionic character. There is a fine line between what seperates the other with these bonds, so AgCl would be on the "borderline" section.
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    thanks for your help are you doing as chemistry?
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    (Original post by tree123)
    thanks for your help are you doing as chemistry?
    Yeap - actually studying A level chemistry at the moment, with AS retakes on their way in January

    However, it feels as though the more wider reading you do in your free time, the more you realise that your teachers/exam boards are just lying to you.
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    (Original post by Another)
    Yeap - actually studying A level chemistry at the moment, with AS retakes on their way in January

    However, it feels as though the more wider reading you do in your free time, the more you realise that your teachers/exam boards are just lying to you.

    Oh ok what board? I'm with Edexcel. Oh did you not get the grades you wanted for AS the first time then? Haha really? How come I would have thought with alevels being more detailed it should be more accurate!
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    (Original post by tree123)
    Oh ok what board? I'm with Edexcel. Oh did you not get the grades you wanted for AS the first time then? Haha really? How come I would have thought with alevels being more detailed it should be more accurate!
    OCR Salters here! I got a B at AS, but I really think that with the amount of effort I put in over the summer that I could have acheived more. The problem was that I didn't look at ANY past exam papers xP

    A levels are more detailed, but don't contain anywhere near enough detail to actually get a proper understanding of things. For one thing, the textbook may miss out a few key terms when defining something, or imply things that aren't true through it's wordings, etc etc... which means major confusion for students. For example, for the answer I just gave you above, I doubt you'll find that in any syllabus at all for AS/A level.

    Our Chemistry teacher will always encourage questions, but ALOT of the time he will say "The answer for that lies in undergraduate-level chemistry study - just learn this for your exams!"
 
 
 
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