AXE

[Melissa Villanueva1K]

Is there a method to figure out a molecule's AXE or do we just have to memorize them in accordance to the shape? Thanks!

[Porus_Karwa_2E]

Well X is the number of possible bonds and E is the number of lone pairs. So you'd have to memorize this combination for each shape.

[Jaifreen_Bhangu_3K]

You just have to memorize it.

[Dimitri Speron 1C]

If you memorize which molecules are the ones without lone pairs, then it is fairly easy to intuit which molecules are the ones with one less atom and a lone pair instead. (identical electron arrangement, different molecular shape) This is the method that I usually use.

[Kelly Zhang 1L]

Can you always determine the molecular shape of a molecule just from the VSEPR notation?

[Chem_Mod]

You can determine the VSEPR formula (AXE) by looking at a molecule. For example, water is sp3 hybridized with AX2E2. This is because there are 2 bonded pairs (between each H and the O) and 2 lone pairs (on the oxygen). If you know an example of a molecule for each molecular geometry or are trying to determine AXE for a molecule, I would suggest drawing the LDMS and counting bonded pairs and lone pairs. If you are determining AXE for a molecule you can do that just by drawing the LDMS.

[Aleeque Marselian 1A]

A is the central atom, X is the number of bonded pairs, ad E is the number of lone pairs. Therefore, you can figure out a molecules AXE by looking at the molecule.

[Nina Do 4L]

When writing the VSEPR formula, you begin with A which is the central atom. And then E and the subscript number will depend on the amount of "things" it's attached to, regardless of bonds. Then you'd finish with E and the subscribe number will depend on the amount of LONE PAIRS. We count everything in pairs, not individually. Hope this helps!