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Arrangement vs Shape

Posted: Thu Nov 15, 2018 11:38 am
by katherinemurk 2B
Can someone please clarify what the difference is when asked for arrangement vs when asked for molecular shape? I know it has something to do with the lone pairs but im not entirely sure

Re: Arrangement vs Shape

Posted: Thu Nov 15, 2018 12:03 pm
by Sofia Ban
I think that when asked for the arrangement, it's asking for all single, double, triple bonds as well as lone pair electrons (Lewis Structure). For molecular shape, it may want just the positioning of the atoms without showing what kinds of bonds are attached (almost like a simple 3D drawing) and the name of the shape (octahedral, linear, trigonal planar, etc.)

Re: Arrangement vs Shape

Posted: Thu Nov 15, 2018 1:19 pm
by Manu Vohra 1L
The arrangement is dependent only on the number of regions of electron density whereas the molecular geometry has to take into account the number of bonded electrons vs. the number of lone pairs and how they interact among each other (lone pairs force bonded atoms closer together and therefore create a different shape and slightly lower bond angle than would be expected of typical molecules with the same arrangement and no lone pairs).

Re: Arrangement vs Shape

Posted: Thu Nov 15, 2018 1:25 pm
by Schem_student
Also you can learn molecular shape alot easier if for some lewis structures you start to draw them similar to their Molecular shape. This can be true for bent, trigonal planar, and seesaw.