Molecular Shape

(Polar molecules, Non-polar molecules, etc.)

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Courtney McHargue 1I
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Molecular Shape

Postby Courtney McHargue 1I » Wed Nov 14, 2018 5:13 pm

What are all the factors that affect molecular shape determined from the lewis structure?

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Re: Molecular Shape

Postby Kobe_Wright » Wed Nov 14, 2018 5:19 pm

The number of bonding atoms (bond type is irrelevant), and the number of lone electrons on the central atom. We can see this in the VSEPR formulas AXE. A= central atom, X= bonding pairs to central atom, E= number of lone electron pairs, each of these is denoted with subscripts telling the quantity of their values.

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Re: Molecular Shape

Postby josephyim1L » Wed Nov 14, 2018 6:03 pm

Once the lewis structure is determined, the molecular shape is ultimately determined by the principle of stability. Due to electron-electron repulsion, the differing bond-pairs or lone-pair electrons want to be distanced as far away as possible on a 3 dimensional plane, this is manifested in the differing shapes that we've been studying (trigonal planar, linear, trigonal pyramidal, etc.)

Kelly Zhang 1L
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Re: Molecular Shape

Postby Kelly Zhang 1L » Wed Nov 14, 2018 9:09 pm

If a structure has 2 single bonds and 2 lone pairs, is the molecular shape tetrahedral but the molecular geometry is bent?

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Re: Molecular Shape

Postby ran2000 » Wed Nov 14, 2018 10:52 pm

Molecular shape is dependent on the areas of electron density around the central atom. It can be divided into two categories:
1. Bonded pairs (single, double and triple)
2. Lone pairs
The repulsion affects the shape further:
lone-lone> lone-bonded> bonded-bonded
These are the main features that affect molecular shape.

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