ELITE COMPREHENSIVE
AP CHEMISTRY PRACTICE EXAM
Advanced Undergraduate Chemistry Level
Spring Examination May 2026
atomic number
The same as the number of protons in the nucleus of an element; it is also the same as the
number of electrons surrounding the nucleus of an element when it is neutrally charged.
mass number
The sum of an atom's neutrons and protons
isotopes
Atoms of an element with different numbers of neutrons
Avogadro's number
6.022×10²³ particles per one mole
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,Moles
grams/molar mass
Standard Temperature and Pressure (STP)
Pressure = 1 atm
Temperature = 273 K
Converting from moles to liters
I mole of gas = 22.4 L
Moles and Solutions
Moles = (molarity)(liters of solution)
percent composition (mass percents)
The percent by mass of each element that makes up a compound. It is calculated by dividing the
mass of each element or component in a compound by the total molar mass for the substance.
empirical formula
- Represents the simplest ratio of one element to another in a compound
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,- Start by assuming a 100 g sample
- Convert percentages to grams
- Convert grams into moles
- Divide each mole value by the lowest of the values
- These values become the subscripts
molecular formula
- Determine the molar mass of the empirical formula
- Divide that mass into the molar mass
x = m/e
x = molar mass/ empirical mass
- Multiply all subscripts in the empirical formula by the value of x
Aufbau principle
States that when building up the electron configuration of an atom, electrons are placed in
orbitals, subshells, and shells in order of increasing energy.
Pauli Exclusion Principle
States that the two electrons which share an orbital cannot have the same spin. One electron
must spin clockwise, and the other must spin counterclockwise.
Hund's Rule
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, States that when an electron is added to a subshell, it will always occupy an empty orbital if no
one is available. Electrons always occupy orbitals singly if possible and pair up only if no empty
orbitals are available.
Coulomb's Law
The amount of energy that an electron has depends on its distance from nucleus of an atom.
While on the exam, you will not be required to mathematically calculate the amount of energy a
given electron has, you should be able to qualitatively apply Coulomb's Law.
Essentially, the greater the charge of the nucleus, the more energy an electron will have.
Quantum Theory
Max Planck figured out that electromagnetic energy is quantized. That is, for a given frequency
of radiation (or light), all possible energies are multiples of a certain unit of energy, called a
quantum (mathematically, that's E = hv). So, energy changes do not occur smoothly but rather
in small but specific steps.
Energy and Electromagnetic Radiation
ΔE = hv = hc/λ
ΔE = energy change
h = Planck's constant, 6.626×10⁻³⁴ J∙s
v = frequency of the radiation
λ = wavelength of the radiation
c = the speed of light, 3.00×10⁸ m/s
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AP CHEMISTRY PRACTICE EXAM
Advanced Undergraduate Chemistry Level
Spring Examination May 2026
atomic number
The same as the number of protons in the nucleus of an element; it is also the same as the
number of electrons surrounding the nucleus of an element when it is neutrally charged.
mass number
The sum of an atom's neutrons and protons
isotopes
Atoms of an element with different numbers of neutrons
Avogadro's number
6.022×10²³ particles per one mole
1|Page
,Moles
grams/molar mass
Standard Temperature and Pressure (STP)
Pressure = 1 atm
Temperature = 273 K
Converting from moles to liters
I mole of gas = 22.4 L
Moles and Solutions
Moles = (molarity)(liters of solution)
percent composition (mass percents)
The percent by mass of each element that makes up a compound. It is calculated by dividing the
mass of each element or component in a compound by the total molar mass for the substance.
empirical formula
- Represents the simplest ratio of one element to another in a compound
2|Page
,- Start by assuming a 100 g sample
- Convert percentages to grams
- Convert grams into moles
- Divide each mole value by the lowest of the values
- These values become the subscripts
molecular formula
- Determine the molar mass of the empirical formula
- Divide that mass into the molar mass
x = m/e
x = molar mass/ empirical mass
- Multiply all subscripts in the empirical formula by the value of x
Aufbau principle
States that when building up the electron configuration of an atom, electrons are placed in
orbitals, subshells, and shells in order of increasing energy.
Pauli Exclusion Principle
States that the two electrons which share an orbital cannot have the same spin. One electron
must spin clockwise, and the other must spin counterclockwise.
Hund's Rule
3|Page
, States that when an electron is added to a subshell, it will always occupy an empty orbital if no
one is available. Electrons always occupy orbitals singly if possible and pair up only if no empty
orbitals are available.
Coulomb's Law
The amount of energy that an electron has depends on its distance from nucleus of an atom.
While on the exam, you will not be required to mathematically calculate the amount of energy a
given electron has, you should be able to qualitatively apply Coulomb's Law.
Essentially, the greater the charge of the nucleus, the more energy an electron will have.
Quantum Theory
Max Planck figured out that electromagnetic energy is quantized. That is, for a given frequency
of radiation (or light), all possible energies are multiples of a certain unit of energy, called a
quantum (mathematically, that's E = hv). So, energy changes do not occur smoothly but rather
in small but specific steps.
Energy and Electromagnetic Radiation
ΔE = hv = hc/λ
ΔE = energy change
h = Planck's constant, 6.626×10⁻³⁴ J∙s
v = frequency of the radiation
λ = wavelength of the radiation
c = the speed of light, 3.00×10⁸ m/s
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