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Molecular Vs. electron

Posted: Fri Jul 08, 2016 5:16 pm
by Sydniespore
What's the difference between electron geometry and molecular geometry?

Re: Molecular Vs. electron  [ENDORSED]

Posted: Fri Jul 08, 2016 5:35 pm
by Hannah_1C
Electron geometry is the arrangement of electron groups (including atoms and lone pairs) while molecular geometry is the arrangements of atoms (excluding lone pairs).
An example in class that explained this difference can be found on pg. 79 when talking about the molecule SO3(2-).
With 3 bonding pairs and 1 lone pair, the 4 pairs have an electron geometry of tetrahedral. However, because only 3 of the 4 positions are occupied by atoms (the other being a lone pair), the molecular geometry is trigonal pyramidal.

Re: Molecular Vs. electron

Posted: Sat Jul 09, 2016 10:45 am
by Vivian Tan 3F
Also keep in mind that the lone pairs do affect the overall shape of the compound: for example, the Lewis structure for H2O seems to be "linear," but because oxygen has 2 lone pairs, they push the hydrogens down, therefore creating the shape "bent."

I think most of the time it'll be asking for molecular geometry.

Re: Molecular Vs. electron

Posted: Sat Jul 09, 2016 12:05 pm
by Rika Jitosho 2E
Knowing that the lone pairs affect the overall shape of the compound--for instance, in H20 the 2 oxygen lone pairs push the hydrogen atoms down to create the bent shape-- for any compound, can we expect that all of the bond angles affected by the repulsion of the lone pairs decrease equally? Thank you!