VSEPR Theory Flashcards

Flashcards on VSEPR Theory and Molecular Shapes

VSEPR Theory

Deals with molecular shapes based on electron densities or domains around a central atom (A).

A (in VSEPR)

Represents the central atom in a molecule.

X (in VSEPR)

Represents an atom bonded to the central atom (A).

E (in VSEPR)

Represents a lone pair on the central atom (A).

Total Domains

Determined by counting atoms and lone pairs around the central atom; do not count bonds.

AX

Generic formula with 1 bonded atom and 0 lone pairs around the central atom, resulting in a linear molecular shape (e.g., H2).

AX2

Generic formula with 2 bonded atoms and 0 lone pairs, resulting in a linear molecular shape (e.g., CO2).

AXE

Generic formula with 1 bonded atom and 1 lone pair, resulting in a linear molecular shape (e.g., CN-).

AX3

Generic formula with 3 bonded atoms and 0 lone pairs, resulting in a trigonal planar molecular shape (e.g., AlBr3).

Bond Angle of AX, AX2, AXE

180 degrees

AX2E

Generic formula with 2 bonded atoms and 1 lone pair, resulting in a bent molecular shape (e.g., SnCl2).

AXE2

Generic formula with 1 bonded atom and 2 lone pairs, resulting in a linear molecular shape (e.g., O2).

Bond angle of AX3, AX2E, AXE2

120 degrees

AX4

Generic formula with 4 bonded atoms and 0 lone pairs, resulting in a tetrahedral molecular shape (e.g., SiCl4).

AX3E

Generic formula with 3 bonded atoms and 1 lone pair, resulting in a trigonal pyramidal molecular shape (e.g., PH3).

AX2E2

Generic formula with 2 bonded atoms and 2 lone pairs, resulting in a bent molecular shape (e.g., SeBr2).

AXE3

Generic formula with 1 bonded atom and 3 lone pairs, resulting in a linear molecular shape (e.g., Cl2).

Bond angle of AX4, AX3E, AX2E2, AXE3

109.5 degrees

AX5

Generic formula with 5 bonded atoms and 0 lone pairs, resulting in a trigonal bipyramidal molecular shape (e.g., AsF5).

AX4E

Generic formula with 4 bonded atoms and 1 lone pair, resulting in a see-saw molecular shape (e.g., SeH4).

AX3E2

Generic formula with 3 bonded atoms and 2 lone pairs, resulting in a T-shaped molecular shape (e.g., ICl3).

AX2E3

Generic formula with 2 bonded atoms and 3 lone pairs, resulting in a linear molecular shape (e.g., BrF2-).

Bond Angles of AX5, AX4E, AX3E2, AX2E3

90 and 120 degrees

AX6

Generic formula with 6 bonded atoms and 0 lone pairs, resulting in an octahedral molecular shape (e.g., SeCl6).

AX5E

Generic formula with 5 bonded atoms and 1 lone pair, resulting in a square pyramidal molecular shape (e.g., IF5).

AX4E2

Generic formula with 4 bonded atoms and 2 lone pairs, resulting in a square planar molecular shape (e.g., XeF4).

Bond Angle of AX6, AX5E, AX4E2

90 degrees

Bonds Representation

All bonds (single, double, or triple) are represented as a line in the provided molecular shape tables.

Domain Count

Any atom bonded to the center atom counts as one domain, even with double or triple bonds.

Total Domains Calculation

The number of bonded atoms plus lone pairs always equals the total number of domains.