Chpter 5: Chemical Bonding I: Drawing Lewis Structures and Determining Molecular Shapes

resonance structure

One of two or more valid Lewis structures shown with double-headed arrows between them to indicate that the actual structure of the molecule is intermediate between them.

resonance hybrid

The actual structure of a molecule that is intermediate between two or more resonance structures.

formal charge

The charge that an atom in a Lewis structure would have if all the bonding electrons were shared equally between the bonded atoms.

bond energy

For a chemical bond, the energy required to break one mole of the bond in the gas phase.

bond length

The average length of a bond between two particular atoms in a variety of compounds.

valence shell electron pair repulsion theory

(VSEPR) A theory that allows prediction of the shapes of molecules based on the idea that electrons—either as lone pairs or as bonding pairs—repel one another.

electron groups

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

linear geometry

The molecular geometry of three atoms that form a 180° bond angle, which results from the repulsion of two electron groups.

trigonal planar geometry

The molecular geometry of four atoms with 120° bond angles in a plane.

tetrahedral geometry

The molecular geometry of five atoms with 109.5° bond angles.

trigonal bypyramidal geometry

The molecular geometry of five atoms with 109.5° bond angles.

octahedral geometry

The molecular geometry of seven atoms with 90° bond angles.

electron geometry

The geometrical arrangement of electron groups in a molecule.

molecular geometry

The geometrical arrangement of atoms in a molecule.

trigonal pyramidal

(trigonal pyramidal geometry) The molecular geometry of a molecule with tetrahedral electron geometry and one lone pair.

square pyramidal

(square pyramidal geometry) The molecular geometry of a molecule with octahedral electron geometry and one lone pair.

square planar

(square planar geometry) he molecular geometry of a molecule with octahedral electron geometry and two lone pairs.

seesaw

(seesaw geometry) The molecular geometry of a molecule with trigonal bipyramidal electron geometry and one lone pair in an axial position.

T-shaped

(T-shaped geometry) The molecular geometry of a molecule with trigonal bipyramidal electron geometry and two lone pairs in axial positions.