11.2 VSEPR Theory: The Five Basic Shapes

valence shell electron pair repulsion (VSEPR)

a theory that allows prediction of the shapes of molecules based on the idea that electron groups repel one another

electron groups

a general term for lone pairs, single bonds, multiple bonds, or lone electrons in a molecule

interior

According to VSEPR theory, the repulsions between electron groups on _________ (interior/terminal) atoms determine the geometry of the molecule.

electron groups, lone pairs

For molecules having just one interior/central atom, molecular geometry depends on (1) the number of ___________________ around the central atom and (2) how many of those are bonding groups and how many are ____________.

6

There are 5 basic arrangements of electron groups based on a maximum of _ electron bonding groups, although there may (in very rare circumstances) by more than that.

false

(true/false) It matters which resonance form is used to determine electron geometry.

linear geometry

the molecular geometry of three atoms with a 180 degree bond angle due to the repulsion of two electron groups

true

(true/false) A double bond counts as one electron group.

trigonal planar geometry

molecular geometry of 4 atoms with 120 degree bond angles in a plane

tetrahedral geometry

the molecular geometry of 5 atoms with 109.5 degree bond angles

trigonal bipyramidal geometry

molecular geometry of 6 atoms with 120 degree bond angles between 3 equatorial electron groups and 90 degree bond angles between 2 axial electron groups and the trigonal plane

octahedral geometry

molecular geometry of 7 atoms with 90 degree bond angles where 4 electron groups lie in a single plane and the 5th and 6th group are respectively above and below the plane