Chemistry - Chapter 4 Vocab

Covalent bond

a bond where share pairs of electrons; ΔEN < 1.7

Ionic bond

A bond where electrons are transferred between atoms; ΔEN ≥ 1.7

Bond energy/strength

inversely proportional to bond length; (number of bonds)/(number of areas)

Polar covalent bond

bonds with a ΔEN between 1.5 and 1.7

Nonpolar covalent bond

bond with an equal sharing of electrons; ΔEN <1.5

Resonance structures

two or more equivalent Lewis structures that describe the bonding in a single molecule or ion, where the atoms' positions are the same but the electron positions differ

Lone pair

valence electrons in an atom that are not bonded

Lewis structure

a diagram of covalent molecules that shows the sharing of valence electrons as well as lone pairs

VSEPR Theory

the idea that electrons repel and get as far as possible from each other. This means that lone pairs repel to change the geometry of a molecule

trigonal planar

electron pair geometry for 3 electron groups

molecular geometry for 3 bonds and 0 lone pairs

bond angle 120 degrees

tetrahedral

electron pair geometry for 4 electron groups

molecular geometry for 4 bonds and 0 lone pairs

bond angle 109.5 degrees

Bent

molecular geometry with 2 bonds and 1 or 2 lone pairs

T-shaped

3 bonds and 2 or 3 lone pairs

Square pyramidal

5 bonds and 1 lone pair

octet rule

each atom wants 8 valence electrons

duet rule

hydrogen and helium want 2 valence electrons

dipole

molecules on opposite ends with unequal sharing of electrons

hybridization

rearrangement of atom orbitals s and p to form bonds

Diatomic molecules

molecules that contain two of the same atom bonded to each other

Bond length

inversely proportional to bond strength

Double bond and triple bond

when atoms share more than two electrons

Electronegativity

the attraction of electrons in a bond

Octahedron

formed by 6 bonds with no lone pairs

Trigonal pyramidal

formed by 3 bonds and 1 lone pair

Linear

180 degree geometry; formed by 2 bonds and 0 lone pairs, 2 bonds and 3 lone pairs, or 2 bonds and 4 lone pairs

seesaw

formed by 4 bonds and 1 lone pair

square planar

formed by 4 bonds and 2 lone pairs

trigonal bipyramidal

120 degrees in a plane and 90 degrees above and below the plane

electron pair geometry for 5 groups of electrons

molecular geometry for 5 bonds and 0 lone pairs