Sigma or Pi
Theories/Terms
Polar or Non
Shapes
Misc.
100

Stronger

Sigma

100

assumption that molecular shapes are largely distributed by repulsion of regions of e- concentration

VSEPR (valence shell electron pair repulsion)

100

determined by 

shape (symmetry)

100

O2

linear

100

δ− or δ+ indicates

partial charge

200

Overlapping orbitals

pi

200

vector sum of all bond polarities that exist in molecule 

dipole moment

200

determined by difference in electronegativity (which polarity)

bond polarity
200
PH3

pyramidal

200

T/F: All molecules must have an octet of electrons to form.

False

300

Overlapping s and/or orbitals

sigma

300

covalent bonds are formed when orbitals of different atoms overlap (gives sigma and pi)

valence bond theory

300

bent: always or sometimes

always

300

N2

linear

300
phenomenon explained by presence of unpaired electrons in orbitals

paramagnetism

400

Double bond-how many of each?

Sigma-1

Pi-1

400

predicts magnetic qualities

molecular orbital

400

tetrahedral: always or sometimes

sometimes

400

CH4

tetrahedral

400

new kinds of orbitals of equal energy are formed from combination of orbitals of different energies

hybridization

500

MgO: How many of each?

1 of each

500

No single Lewis structure completely describes e- distribution

resonance

500

NH3

polar (pyramidal)

500

H2S

bent

500

clotting material that stops bleeding through charge attraction

chitosan