AP®︎ Chemistry: Topic 2.7 Flashcards
Master key terms and definitions for Topic 2.7 of AP Chemistry – VSEPR and Hybridization to help you prep for quizzes and the AP exam.
VSEPR Theory
Electron pairs arrange around a central atom to minimize Coulombic repulsion.
Electron pairs arrange around a central atom to minimize Coulombic repulsion.
Draw the Lewis structure, count electron domains, find electron geometry, then ignore lone pairs for shape.
Regions of electron density around a central atom, including bonds and lone pairs.
A formula where A is central atom, X is bonded atoms, and E is lone pairs.
Electron geometry includes all domains; molecular geometry describes only atom positions.
Linear 180°, trigonal planar 120°, bent <120° or <109.5°, tetrahedral 109.5°, trigonal pyramidal ~107°, trigonal bipyramidal 90°/120°/180°, seesaw distorted, T-shaped ~90°, octahedral 90°, square pyramidal <90°, square planar 90°.
Nonbonding pairs repel more strongly than bonding pairs and compress bond angles.
Six electron domains arranged symmetrically with 90° angles between adjacent positions.
Mixing of valence orbitals to form equivalent orbitals that match electron-domain geometry.
sp gives linear 180°, sp2 gives trigonal planar 120°, sp3 gives tetrahedral 109.5°.
Sigma bonds form by head-on overlap; pi bonds form by sideways overlap of parallel p orbitals.
Single bonds are 1σ, double bonds are 1σ+1π, and triple bonds are 1σ+2π.
Head-on overlap is stronger than sideways overlap, so sigma bonds have greater bond energy.
Higher bond order gives shorter, stronger bonds; lower bond order gives longer, weaker bonds.
For similar bond orders, larger bonded atoms form longer bonds than smaller atoms.
Delocalized bonding can make multiple bonds equivalent, giving the same intermediate bond length.
Count one sigma in every bond, then add one pi for each double and two for each triple.
Five electron domains form three equatorial and two axial positions, with lone pairs equatorial first.
A molecule is polar when polar bond dipoles do not cancel because of its geometry.
Pi bonds restrict rotation, allowing cis-trans isomers with different spatial arrangements across double bonds.
Unequal electron sharing in a bond caused by a difference in electronegativity.
