Mention Lesson Goals for each topic. Group anything with a similar code(SPQ, SAP, TRA, ENE)
SPQ-1.A.1
One cannot count particles directly while
performing laboratory work. Thus, there must
be a connection between the masses of
substances reacting and the actual number of
particles undergoing chemical changes.
SPQ-1.A.2
Avogadro’s number (N = 6.022 × 1023 mol−1
A )
provides the connection between the number
of moles in a pure sample of a substance and
the number of constituent particles (or formula
units) of that substance.
SPQ-1.A.3
Expressing the mass of an individual atom
or molecule in atomic mass units (amu) is
useful because the average mass in amu of
one particle (atom or molecule) or formula
unit of a substance will always be numerically
equal to the molar mass of that substance
in grams. Thus, there is a quantitative
connection between the mass of a substance
and the number of particles that the
substance contains.
EQN: n = m/M
SPQ-1.B.1
The mass spectrum of a sample containing a
single element can be used to determine the
identity of the isotopes of that element and the
relative abundance of each isotope in nature.
SPQ-1.B.2
The average atomic mass of an element can
be estimated from the weighted average of
the isotopic masses using the mass of each
isotope and its relative abundance.
X INTERPRETING MASS SPECTRA
Interpreting mass spectra of samples
containing multiple elements or peaks arising
from species other than singly charged
monatomic ions will not be assessed on
the AP Exam.
SPQ-2.A.1
Some pure substances are composed of
individual molecules, while others consist
of atoms or ions held together in fixed
proportions as described by a formula unit.
SPQ-2.A.2
According to the law of definite proportions,
the ratio of the masses of the constituent
elements in any pure sample of that compound
is always the same.
SPQ-2.A.3
The chemical formula that lists the lowest
whole number ratio of atoms of the elements in
a compound is the empirical formula.
SPQ-2.B.1
While pure substances contain molecules or
formula units of a single type, mixtures contain
molecules or formula units of two or more
types, whose relative proportions can vary.
SPQ-2.B.2
Elemental analysis can be used to determine
the relative numbers of atoms in a substance
and to determine its purity
SAP-1.A.1
The atom is composed of negatively charged
electrons and a positively charged nucleus that
is made of protons and neutrons.
SAP-1.A.2
Coulomb’s law is used to calculate the force
between two charged particles.
EQN: Fcoulombic ∝ q1
q2
r2
SAP-1.A.3
In atoms and ions, the electrons can be thought
of as being in “shells (energy levels)” and
“subshells (sublevels),” as described by the
electron configuration. Inner electrons are called
core electrons, and outer electrons are called
valence electrons. The electron configuration is
explained by quantum mechanics, as delineated
in the Aufbau principle and exemplified in the
periodic table of the elements.
X THE ASSIGNMENT OF QUANTUM NUMBERS
TO ELECTRONS IN SUBSHELLS OF AN
ATOM WILL NOT BE ASSESSED ON THE
AP EXAM.
Rationale: Assignment of quantum numbers
to electrons in specific subshells does not
increase students’ understanding of the
structure of the atom.
SAP-1.A.4
The relative energy required to remove an
electron from different subshells of an atom or
ion or from the same subshell in different atoms
or ions (ionization energy) can be estimated
through a qualitative application of Coulomb’s
law. This energy is related to the distance from
the nucleus and the effective (shield) charge of
the nucleus. SAP-1.B.1
The energies of the electrons in a given
shell can be measured experimentally with
photoelectron spectroscopy (PES). The
position of each peak in the PES spectrum is
related to the energy required to remove an
electron from the corresponding subshell, and
the height of each peak is (ideally) proportional
to the number of electrons in that subshell.
SAP-2.A.1
The organization of the periodic table is based
on the recurring properties of the elements and
explained by the pattern of electron configurations
and the presence of completely or partially filled
shells (and subshells) of electrons in atoms.
X WRITING THE ELECTRON CONFIGURATION
OF ELEMENTS THAT ARE EXCEPTIONS
TO THE AUFBAU PRINCIPLE WILL NOT BE
ASSESSED ON THE AP EXAM.
Rationale: The mere rote recall of the
exceptions does not match the goals of the
curriculum revision.
SAP-2.A.2
Trends in atomic properties within the
periodic table (periodicity) can be qualitatively
understood through the position of the element
in the periodic table, Coulomb’s law, the shell
model, and the concept of shielding/effective
nuclear charge. These properties include:
a. Ionization energy
b. Atomic and ionic radii
c. Electron affinity
d. Electronegativity.
SAP-2.A.3
The periodicity (in SAP-2.A.2) is useful to
predict /estimate values of properties in the
absence of data.SAP-2.B.1
The likelihood that two elements will form
a chemical bond is determined by the
interactions between the valence electrons
and nuclei of elements.
SAP-2.B.2
Elements in the same column of the periodic
table tend to form analogous compounds.
SAP-2.B.3
Typical charges of atoms in ionic compounds
are governed by their location on the periodic
table and the number of valence electrons. 
SAP-3.A.1
Electronegativity values for the representative
elements increase going from left to right
across a period and decrease going down
a group. These trends can be understood
qualitatively through the electronic structure of
the atoms, the shell model, and Coulomb’s law.
SAP-3.A.2
Valence electrons shared between atoms
of similar electronegativity constitute a
nonpolar covalent bond. For example, bonds
between carbon and hydrogen are effectively
nonpolar even though carbon is slightly more
electronegative than hydrogen.
SAP-3.A.3
Valence electrons shared between atoms of
unequal electronegativity constitute a polar
covalent bond.
a. The atom with a higher electronegativity will
develop a partial negative charge relative to
the other atom in the bond.
b. In single bonds, greater differences in
electronegativity lead to greater bond dipoles.
c. All polar bonds have some ionic character,
and the difference between ionic and
covalent bonding is not distinct but rather
a continuum.
SAP-3.A.4
The difference in electronegativity is not the
only factor in determining if a bond should
be designated as ionic or covalent. Generally,
bonds between a metal and nonmetal are
ionic, and bonds between two nonmetals are
covalent. Examination of the properties of a
compound is the best way to characterize the
type of bonding.
SAP-3.A.5
In a metallic solid, the valence electrons
from the metal atoms are considered to be
delocalized and not associated with any
individual atom.
SAP-3.B.1
A graph of potential energy versus the distance
between atoms is a useful representation for
describing the interactions between atoms.
Such graphs illustrate both the equilibrium
bond length (the separation between atoms at
which the potential energy is lowest) and the
bond energy (the energy required to separate
the atoms).
SAP-3.B.2
In a covalent bond, the bond length is
influenced by both the size of the atom’s core
and the bond order (i.e., single, double, triple).
Bonds with a higher order are shorter and have
larger bond energies.
SAP-3.B.3
Coulomb’s law can be used to understand the
strength of interactions between cations
and anions.
a. Because the interaction strength is
proportional to the charge on each ion, larger
charges lead to stronger interactions.
b. Because the interaction strength increases
as the distance between the centers of the
ions (nuclei) decreases, smaller ions lead to
stronger interactions.
SAP-3.C.1
The cations and anions in an ionic crystal are
arranged in a systematic, periodic 3-D array
that maximizes the attractive forces among
cations and anions while minimizing the
repulsive forces.
X KNOWLEDGE OF SPECIFIC TYPES OF
CRYSTAL STRUCTURES WILL NOT BE
ASSESSED ON THE AP EXAM.
Rationale: Study of specific crystal structures is
not essential to an understanding of the big ideas.
SAP-3.D.1
Metallic bonding can be represented as an
array of positive metal ions surrounded by
delocalized valence electrons (i.e., a “sea
of electrons”).
SAP-3.D.2
Interstitial alloys form between atoms of
different radii, where the smaller atoms fill the
interstitial spaces between the larger atoms
(e.g., with steel in which carbon occupies the
interstices in iron).
SAP-3.D.3
Substitutional alloys form between atoms
of comparable radius, where one atom
substitutes for the other in the lattice. (In
certain brass alloys, other elements, usually
zinc, substitute for copper.)
SAP-4.A.1
Lewis diagrams can be constructed according
to an established set of principles.
SAP-4.B.1
In cases where more than one equivalent Lewis
structure can be constructed, resonance
must be included as a refinement to the Lewis
structure. In many such cases, this refinement
is needed to provide qualitatively accurate
predictions of molecular structure
and properties.
SAP-4.B.2
The octet rule and formal charge can be used
as criteria for determining which of several
possible valid Lewis diagrams provides the
best model for predicting molecular structure
and properties.
SAP-4.B.3
As with any model, there are limitations to
the use of the Lewis structure model,
particularly in cases with an odd number of
valence electrons. 
SAP-4.C.1
VSEPR theory uses the Coulombic repulsion
between electrons as a basis for predicting
the arrangement of electron pairs around a
central atom.
SAP-4.C.2
Both Lewis diagrams and VSEPR theory must
be used for predicting electronic and structural
properties of many covalently bonded
molecules and polyatomic ions, including
the following:
a. Molecular geometry
b. Bond angles
c. Relative bond energies based on bond order
d. Relative bond lengths (multiple bonds,
effects of atomic radius)
e. Presence of a dipole moment
f. Hybridization of valence orbitals of
the molecule
SAP-4.C.3
The terms “hybridization” and “hybrid atomic
orbital” are used to describe the arrangement
of electrons around a central atom. When the
central atom is sp hybridized, its ideal bond
angles are 180°; for sp2 hybridized atoms the
bond angles are 120°; and for sp3 hybridized
atoms the bond angles are 109.5°.
X AN UNDERSTANDING OF THE DERIVATION
AND DEPICTION OF HYBRID ORBITALS
WILL NOT BE ASSESSED ON THE AP EXAM.
Rationale: The course includes the distinction
between sigma and pi bonding, the use of VSEPR
to explain the shapes of molecules, and the sp,
sp2
, and sp3
 nomenclature. Additional aspects
related to hybridization are both controversial and
do not substantially enhance understanding of
molecular structure.
X HYBRIDIZATION INVOLVING D ORBITALS
WILL NOT BE ASSESSED ON THE AP EXAM.
WHEN AN ATOM HAS MORE THAN FOUR
PAIRS OF ELECTRONS SURROUNDING THE
CENTRAL ATOM, STUDENTS ARE ONLY
RESPONSIBLE FOR THE SHAPE OF THE
RESULTING MOLECULE.
Rationale: Current evidence suggests that
main-group hybridization involving d orbitals
does not exist, and there is controversy about the
need to teach any hybridization. Until agreement
is reached in the chemistry community, we
will continue to include only sp, sp2
, and sp3
hybridization on the AP Exam.
SAP-4.C.4
Bond formation is associated with overlap
between atomic orbitals. In multiple bonds, such
overlap leads to the formation of both sigma
and pi bonds. The overlap is stronger in sigma
than pi bonds, which is reflected in sigma bonds
having greater bond energy than pi bonds. The
presence of a pi bond also prevents the rotation
of the bond and leads to structural isomers.
X MOLECULAR ORBITAL THEORY IS
RECOMMENDED AS A WAY TO PROVIDE
DEEPER INSIGHT INTO BONDING.
HOWEVER, THE AP EXAM WILL NEITHER
EXPLICITLY ASSESS MOLECULAR ORBITAL
DIAGRAMS, FILLING OF MOLECULAR
ORBITALS, NOR THE DISTINCTION
BETWEEN BONDING, NONBONDING, AND
ANTIBONDING ORBITALS.
Rationale: As currently covered in general
chemistry college textbooks, molecular orbital
theory is limited to homonuclear molecules in the
second period.
SAP-5.A.1
London dispersion forces are a result of the
Coulombic interactions between temporary,
fluctuating dipoles. London dispersion forces
are often the strongest net intermolecular
force between large molecules.
a. Dispersion forces increase with increasing
contact area between molecules and with
increasing polarizability of the molecules.
b. The polarizability of a molecule increases
with an increasing number of electrons in the
molecule; and the size of the electron cloud.
It is enhanced by the presence of pi bonding.
c. The term “London dispersion forces” should
not be used synonymously with the term
“van der Waals forces.”
SAP-5.A.2
The dipole moment of a polar molecule
leads to additional interactions with other
chemical species.
a. Dipole-induced dipole interactions are
present between a polar and nonpolar
molecule. These forces are always attractive.
The strength of these forces increases with
the magnitude of the dipole of the polar
molecule and with the polarizability of the
nonpolar molecule.b. Dipole-dipole interactions are present
between polar molecules. The interaction
strength depends on the magnitudes of
the dipoles and their relative orientation.
Interactions between polar molecules
are typically greater than those between
nonpolar molecules of comparable size
because these interactions act in addition to
London dispersion forces.
c. Ion-dipole forces of attraction are present
between ions and polar molecules.
These tend to be stronger than dipoledipole forces.
SAP-5.A.3
The relative strength and orientation
dependence of dipole-dipole and ion-dipole
forces can be understood qualitatively by
considering the sign of the partial charges
responsible for the molecular dipole moment,
and how these partial charges interact with an
ion or with an adjacent dipole.
SAP-5.A.4
Hydrogen bonding is a strong type of
intermolecular interaction that exists when
hydrogen atoms covalently bonded to the
highly electronegative atoms (N, O, and F)
are attracted to the negative end of a dipole
formed by the electronegative atom (N, O,
and F) in a different molecule, or a different part
of the same molecule.
SAP-5.A.5
In large biomolecules, noncovalent interactions
may occur between different molecules
or between different regions of the same
large biomolecule.
SAP-5.B.1
Many properties of liquids and solids are
determined by the strengths and types of
intermolecular forces present. Because
intermolecular interactions are broken when a
substance vaporizes, the vapor pressure and
boiling point are directly related to the strength
of those interactions. Melting points also tend
to correlate with interaction strength, but
because the interactions are only rearranged,
in melting, the relations can be more subtle.
SAP-5.B.2
Particulate-level representations, showing
multiple interacting chemical species, are a
useful means to communicate or understand
how intermolecular interactions help to
establish macroscopic properties.
SAP-5.B.3
Due to strong interactions between ions,
ionic solids tend to have low vapor pressures,
high melting points, and high boiling points.
They tend to be brittle due to the repulsion
of like charges caused when one layer slides
across another layer. They conduct electricity
only when the ions are mobile, as when the
ionic solid is melted or dissolved in water or
another solvent.
SAP-5.B.4
In covalent network solids, the atoms are
covalently bonded together into a threedimensional network (e.g., diamond) or layers
of two-dimensional networks (e.g., graphite).
These are only formed from nonmetals:
elemental (e.g., diamond, graphite) or binary
compounds of two nonmetals (e.g., silicon
dioxide and silicon carbide). Due to the strong
covalent interactions, covalent solids have high
melting points. Three-dimensional network
solids are also rigid and hard, because the
covalent bond angles are fixed. However,
graphite is soft because adjacent layers can
slide past each other relatively easily.
SAP-5.B.5
Molecular solids are composed of distinct,
individual units of covalently-bonded
molecules attracted to each other through
relatively weak intermolecular forces. Molecular
solids generally have a low melting point
because of the relatively weak intermolecular
forces present between the molecules. They
do not conduct electricity because their
valence electrons are tightly held within the
covalent bonds and the lone pairs of each
constituent molecule. Molecular solids are
sometimes composed of very large molecules
or polymers.
SAP-5.B.6
Metallic solids are good conductors of
electricity and heat, due to the presence of
free valence electrons. They also tend to be
malleable and ductile, due to the ease with
which the metal cores can rearrange their
structure. In an interstitial alloy, interstitial
atoms tend to make the lattice more rigid,
decreasing malleability and ductility. Alloys
typically retain a sea of mobile electrons and so
remain conducting.
SAP-5.B.7
In large biomolecules or polymers, noncovalent
interactions may occur between different
molecules or between different regions of the
same large biomolecule. The functionality and
properties of such molecules depend strongly
on the shape of the molecule, which is largely
dictated by noncovalent interactions.
SAP-6.A.1
Solids can be crystalline, where the particles
are arranged in a regular three-dimensional
structure, or they can be amorphous, where
the particles do not have a regular, orderly
arrangement. In both cases, the motion of the
individual particles is limited, and the particles
do not undergo overall translation with respect
to each other. The structure of the solid is
influenced by interparticle interactions and the
ability of the particles to pack together.
SAP-6.A.2
The constituent particles in liquids are in
close contact with each other, and they
are continually moving and colliding. The
arrangement and movement of particles are
influenced by the nature and strength of the
forces (e.g., polarity, hydrogen bonding, and
temperature) between the particles.
SAP-6.A.3
The solid and liquid phases for a particular
substance typically have similar molar volume
because, in both phases, the constituent
particles are in close contact at all times.
SAP-6.A.4
In the gas phase, the particles are in constant
motion. Their frequencies of collision and the
average spacing between them are dependent
on temperature, pressure, and volume. Because
of this constant motion, and minimal effects of
forces between particles, a gas has neither a
definite volume nor a definite shape.
X UNDERSTANDING/INTERPRETING PHASE
DIAGRAMS WILL NOT BE ASSESSED ON
THE AP EXAM.
Rationale: Phase diagrams of pure substances
are considered prior knowledge.
SAP-7.A.1
The macroscopic properties of ideal gases are
related through the ideal gas law:
EQN: PV = nRT.
SAP-7.A.2
In a sample containing a mixture of ideal gases,
the pressure exerted by each component (the
partial pressure) is independent of the other
components. Therefore, the total pressure of
the sample is the sum of the partial pressures.
EQN: PA = Ptotal × XA,
where XA = moles A/total moles;
EQN: Ptotal = PA + PB + PC + …
SAP-7.A.3
Graphical representations of the relationships
between P, V, T, and n are useful to describe
gas behavior.
SAP-7.B.1
The kinetic molecular theory (KMT) relates
the macroscopic properties of gases to
motions of the particles in the gas. The
Maxwell-Boltzmann distribution describes the
distribution of the kinetic energies of particles
at a given temperature.
SAP-7.B.2
All the particles in a sample of matter are in
continuous, random motion. The average
kinetic energy of a particle is related to its
average velocity by the equation:
EQN: KE = ½ mv2
.
SAP-7.B.3
The Kelvin temperature of a sample of matter
is proportional to the average kinetic energy of
the particles in the sample.
SAP-7.B.4
The Maxwell-Boltzmann distribution provides
a graphical representation of the energies/
velocities of particles at a given temperature.
SAP-7.C.1
The ideal gas law does not explain the actual
behavior of real gases. Deviations from the
ideal gas law may result from interparticle
attractions among gas molecules, particularly
at conditions that are close to those resulting in
condensation. Deviations may also arise from
particle volumes, particularly at extremely
high pressures. 
SPQ-3.A.1
Solutions, also sometimes called
homogeneous mixtures, can be solids, liquids,
or gases. In a solution, the macroscopic
properties do not vary throughout the sample.
In a heterogeneous mixture, the macroscopic
properties depend on location in the mixture.
SPQ-3.A.2
Solution composition can be expressed in a
variety of ways; molarity is the most common
method used in the laboratory.
EQN: M = nsolute /Lsolution
SPQ-3.B.1
Particulate representations of solutions
communicate the structure and properties
of solutions, by illustration of the relative
concentrations of the components in the
solution and drawings that show interactions
among the components.
X COLLIGATIVE PROPERTIES WILL NOT BE
ASSESSED ON THE AP EXAM.
X CALCULATIONS OF MOLALITY, PERCENT
BY MASS, AND PERCENT BY VOLUME WILL
NOT BE ASSESSED ON THE AP EXAM.
SPQ-3.C.1
The components of a liquid solution cannot
be separated by filtration. They can, however,
be separated using processes that take
advantage of differences in the intermolecular
interactions of the components.
a. Chromatography (paper, thin-layer, and
column) separates chemical species by
taking advantage of the differential strength
of intermolecular interactions between and
among the components of the solution
(the mobile phase) and with the surface
components of the stationary phase.
b. Distillation separates chemical species by
taking advantage of the differential strength
of intermolecular interactions between and
among the components and the effects
these interactions have on the vapor
pressures of the components in the mixture.
SPQ-3.C.2
Substances with similar intermolecular
interactions tend to be miscible or soluble in
one another.
SAP-8.A.1
Differences in absorption or emission of
photons in different spectral regions are
related to the different types of molecular
motion or electronic transition:
a. Microwave radiation is associated with
transitions in molecular rotational levels.
b. Infrared radiation is associated with
transitions in molecular vibrational levels.
c. Ultraviolet/visible radiation is associated with
transitions in electronic energy levels.SAP-8.B.1
When a photon is absorbed (or emitted) by an
atom or molecule, the energy of the species is
increased (or decreased) by an amount equal
to the energy of the photon.
SAP-8.B.2
The wavelength of the electromagnetic wave is
related to its frequency and the speed of light
by the equation:
EQN: c = λν.
The energy of a photon is related to the
frequency of the electromagnetic wave
through Planck’s equation (E = ℎν). 
SAP-8.C.1
The Beer-Lambert law relates the absorption of
light by a solution to three variables according
to the equation:
EQN: A = Ebc.
The molar absorptivity E describes how
intensely a sample of molecules or ions
absorbs light of a specific wavelength.
The path length b and concentration
c are proportional to the number of
absorbing species.
SAP-8.C.2
In most experiments the path length and
wavelength of light are held constant. In
such cases, the absorbance is proportional
only to the concentration of absorbing
molecules or ions.