AP Chemistry Unit 2

chemical bonds

the attractive forces that hold atoms together

ionic bond

A chemical bond resulting from the attraction between oppositely charged ions.

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them

octet rule

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons

lattice energy

the energy released when one mole of an ionic crystalline compound is formed from gaseous ions

single bond

a covalent bond in which two atoms share one pair of electrons

double bond

A covalent bond in which two pairs of electrons are shared between two atoms

triple bond

a covalent bond in which two atoms share three pairs of electrons

bond length

the average distance between the nuclei of two bonded atoms

bond polarity

a measure of how equally or unequally the electrons in any covalent bond are shared

polar covalent bond

A covalent bond in which electrons are not shared equally

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons

polar molecule

A molecule that has electrically charged areas.

dipole

created by equal but opposite charges in a polar molecule

formal charge

The number of valence electrons in an isolated atom minus the number of electrons assigned to the atom in the Lewis structure

resonance structure

one of the two or more equally valid electron dot structures of a molecule or polyatomic ion

bond angle

the angle formed by two bonds to the same atom

VSEPR theory

Valence-shell electron-pair repulsion theory; because electron pairs repel, molecules adjust their shapes so that valence electron pairs are as far apart as possible

electron domain

in the VSEPR model, a region about a central atom in which an electron pair is concentrated (could be unshared or bonded pair)

bonding pair

an electron pair found in the space between two atoms

nonbonding pairs

two paired valence electrons that tend not to participate in a chemical bond

bond dipole

separation of electrical charge created when atoms with different electronegativities form a covalent bond

hybrid orbitals

orbitals of equal energy produced by the combination of two or more orbitals on the same atom

hybridization

the mixing of several atomic orbitals to form the same total number of equivalent hybrid orbitals

sp hybridization

linear; bond angle: 180
a type of bonding where the 2s orbital mixes with only one of the three p-orbitals resulting in two sp orbitals and two remaining unchanged p orbitals

sp2 hybridization

1. Trigonal planar structure
2. sp2 hybridization creates 3 identical orbitals of intermediate energy and length and leaves one unhybridized p orbital
3. 3 effective pairs of electrons surround the carbon (double bond treated
as one effective pair)

sp3 hybridization

A type of hybridization that results from the combination of the s orbital and all three p orbitals in the second energy level of carbon, resulting in four hybrid orbitals and occurs when a carbon atom is bonded to four other atoms. The geometric arrangement of those four hybrid orbitals is called tetrahedral.

sigma bond

a bond formed when two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting the two atomic nuclei

pi bond

a bond that is formed when parallel orbitals overlap to share electrons.

metallic solids

solids that have metal atoms occupying the crystal lattice and held together by metallic bonding

ionic solids

solids whose composite units are ions; they generally have high melting points

alloys

a mixture composed of two or more elements, at least one of which is a metal

substitutional alloy

some of the host metal atoms are replaced by other metal atoms of similar sizes

interstitial alloy

a mixture formed when small atoms fill holes in a metallic crystal

electron sea model

Proposes that all metal atoms in a metallic solid contribute their valence electrons to form a "sea" of electrons, and can explain properties of metallic solids such as malleability, conduction, and ductility.

delocalized electrons

electrons that are free to move

linear

180 degrees

trigonal planar

120 degrees

tetrahedral

109.5 degrees

trigonal bipyramidal

120, 180, and 90 degrees

octahedral

90 and 180 degrees

trigonal pyramidal

3 bonds, 1 lone pair

bent

2 bonds, 2 lone pairs

see-saw

4 bonds, 1 lone pair

T-shape

3 bonds, 2 lone pairs

square pyramidal

5 bonds, 1 lone pair

square planar

4 bonds, 2 lone pairs

luster

(n.) the quality of giving off light, brightness, glitter, brilliance

malleable

easy to shape or bend

ductile

can be drawn into wires

electronegativity difference

The difference in electronegativity between two elements in a bond.

Coulomb's Law

F=K q₁*q₂/r², magnitude of force between two charges

ion

A charged atom

polyatomic ion

a tightly bound group of atoms that behaves as a unit and has a positive or negative charge

bond distance (bond length)

the distance between the nuclei of two bonded atoms

free radical

an atom or a group of atoms that has one unpaired electron

resonance

the bonding in molecules or ions that cannot be correctly represented by a single Lewis structure

bond order

the number of bonds between atoms: 1 for a single bond, 2 for a double bond, and 3 for a triple bond

diatomic molecule

a molecule containing only two atoms

oxyacid

an acid that is a compound of hydrogen, oxygen, and a third element, usually a nonmetal

electrical conductivity

the ability of an object to transfer electric current

molten

made liquid by heat; melted

partial charge

unequal distribution of electrons caused by a polar covalent bond

valence electron

an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties

brittle

easily broken