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Can anyone help with my AS chemistry homework? watch

    • Thread Starter

    It’s shapes of molecules and I don’t understand whatsoever but my teacher told me to “google it”. Great! if anyone can do one as an example and explain how they got it? So here it is...

    PCl 6- ion
    SO4 2- ion
    NO3 1- ion
    NO2 1- ion
    NH4 1+ ion
    SO3 2- ion
    CH3 1+ ion
    CH3 1- ion
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    I love these videos:


    You (probably) won't need to know about formal charge, but it is interesting and would lead to a correct set of bonds. If you don't care about it, just getting the number of bonding regions (and lone pairs) is good enough to work out the shapes.

    I struggled with bond shapes and angles too last year so I know your pain!

    So basically how we work it out is:

    1) Fine the central atom

    2) Work out how many electrons are in the outer shell (whatever group it's in)

    3) Add the bonds (so if it is bonding to two molecules add 2 to your number from step 2)

    4) Add the charge (if it is 2- add two to the above number, 2+ minus two from the above number)

    5) Divide the number you have by 2 to get the number of electron pairs

    6) Find the lone pairs (This will be your answer to step 5 take away the number of bonds your molecule has)

    7) Name the bond shape and angle (You have to memorise these for the exam but for now you can find a table in google)

    There's probably many different ways to work it out, so just find the best for you (I hope this made sense)!
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Updated: October 12, 2017

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