Unit 4 Chemistry Vocabulary

Covalent bond

when atoms share a pair of electrons to become stable

Ionic bond

bond between two oppositely charged ions

Bond energy/strength

the amount of energy required to break a chemical bond

Polar covalent bond

neither atom becomes an ion but one “controls” the bonded electron more

Nonpolar covalent bond

neither atom is an ion and the bond has no polarity

Resonance

when multiple e- are delocalized (being shared in multiple places); all the best Lewis structures for a molecule

Lone pair

two electrons in the valence shell of an atom that do not participate in bonding

Lewis structure

shows distribution of valence electrons in a molecule

Duet rule

an atom has received a noble gas configuration for He specifically

Octet rule

an atom has achieved a standard ful valence sublevel

Dipole

polar bonds mean that the sharing of electrons is a little closer to one atom than another; arrow determined by partial negative charge

Hybridization

orbital overlap (s & p), named based on how many BZ/LP are around the central atom

Diatomic element(s)

Bond length

the distance between the nuclei of two atoms

Single bond

two atoms sharing 2 electrons

Double bond

two atoms sharing 4 electrons

Triple bond

two atoms sharing 6 electrons

Electronegativity

the tendency for an atom to attract; used to determine delta chi

VSEPR theory

valence shell electron pair repulsion; the way a molecule will form in a 3D model based on the BZ/LP

Linear (sp, sp3d, sp3d2)

2/0 180; 2/3 180; 2/4 180

Bent (sp2, sp3)

2/1 120, 2/2 109.5

Trigonal planar (sp2)

3/0 120

Tetrahedral (sp3)

4/0 109.5

Trigonal pyramidal (sp3)

3/1 109.5

Trigonal Bipyramidal (sp3d)

5/0 120&90

Octahedral (sp3d2)

6/0 90

See saw (sp3d)

4/1 120&90

Square Planar (sp3d2)

4/2 90

Square Pyramidal (sp3d2)

5/1 90

T Shaped (sp3d, sp3d2)

3/2 90; 3/3 90