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

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Postby duenezjuleny1D » Wed Jul 31, 2019 2:03 am

What is the difference between a vsepr formula and Lewis structures? What exactly is a vsepr formula supposed to look

Ethan McCarthy 1F
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Postby Ethan McCarthy 1F » Wed Jul 31, 2019 7:53 am

The VSEPR formula denotes the number of atoms and lone pairs connected to the central atom using ambiguous letters and numbers (A, X, and E, which still inform us of the molecule's geometry and shape).

A = the central atom
X = the number of atoms bonded to the central atom
E = the number of lone pairs on the central atom

For the molecular formula CH4, the VSEPR formula is AX4

For the molecular formula :NH3, the VSEPR formula is AX3E (where the one lone pair is implied by an "invisible" subscript 1 after the E)

Eva Zhao 4I
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Postby Eva Zhao 4I » Sat Nov 16, 2019 8:14 pm

Lewis structures are 2-D representations of molecular shape and indicate the approximate location of bonding e- and lone pair e-.

The VSEPR Model, or the Valence-Shell Electron-Pair Repulsion Model, explains the experimentally observed shape of molecules. Note that the VSEPR Model can predict distortions qualitatively but not quantitatively.

The notation used in the VSEPR Model is:
A: Central atom
X: Bonded atom
E: Lone pair
As such, NH3 is denoted AX3E and H2O is denoted AX2E2.

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