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Chem qu! please help (THINK: So that would belong in Chemistry then ?) watch

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    hey, im doing my chem 5 and 6 on tuesday, just doing past paper questions now and its not going well and i need an A!!!!!!!!!! grrrrrrr.......... just wondering if anyone can help me with the following question:

    In which of the following molecules do all the atoms lie in the same plane of molecules?
    (i)BCL3
    (ii)HCHO
    (iii)C2H2Br2
    (iv)NH3

    And how do you know?
    any help would be greatly appreciated!
    thanx ppl and good luck with the rest of ur exams everyone!
    :confused:
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    (Original post by britney)
    hey, im doing my chem 5 and 6 on tuesday, just doing past paper questions now and its not going well and i need an A!!!!!!!!!! grrrrrrr.......... just wondering if anyone can help me with the following question:

    In which of the following molecules do all the atoms lie in the same plane of molecules?
    (i)BCL3
    (ii)HCHO
    (iii)C2H2Br2
    (iv)NH3

    And how do you know?
    any help would be greatly appreciated!
    thanx ppl and good luck with the rest of ur exams everyone!
    :confused:
    The shape depends on how many negative centres the molecule has i.e. lone pairs and bond pairs.
    The negative centres will be arranged in such a way that the repulsion between electrons is a minimum.

    (i)3 bond pairs -> trigonal planar
    (ii)3 bond pairs -> trigonal planar
    (ii)3 bond pairs + 1 lone pair -> trigonal pyrimidal (it is not tetrahedral because the shape does not show the lone pair)
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    aint that moderator who puts THINK: infront of yer thread such a ******!, just coz he/she's got nothing better to do, get a better job where they pay u!
 
 
 

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