Egyptian American International School
The Science Department 2015-2016
MID YEAR EXAM STUDY GUIDE
Gr. 12 Chemistry
The Exam Duration 2 Hours
The exam includes the following:
PART A: 50 Multiple Choice questions
PART B: 10 COMPLETE
PART C: 10 Matching
PART D: 10 TRUE OR FALSE
PART E: 10 SHORT ESSAYS
PART F: 5 Problems
PART G: BONUS
The exam includes:
Chapter 11: Modern Atomic Theory
Vocabulary:
Electromagnetic radiation
Sublevels
Lanthanide series
Wavelength
Pauli exclusion principle
Actinide series
Frequency
Auf Bau principle
Main-group elements
Photons
Hund’s rule
(representative elements)
Quantized
Electron configuration
Metals
Wave mechanical model
Orbital diagram (box diagram)
Nonmetals
Orbital
Valence electrons
Metalloids.
Principal energy levels
Core electrons
11.1 Atoms and Energy
 Rutherford’s atom consists of a tiny, dense nucleus at the center and electrons which occupy most of the volume of the
atom.
 Electromagnetic radiation
Characterized by its wavelength and frequency
Can be thought of as a stream of packets of energy called photons
Atoms can gain energy by absorbing a photon or lose energy by emitting a photon.
 The photoelectric effect.
11.2 The Hydrogen Atom
 The hydrogen atom can emit only certain energies as it changes from a higher to a lower energy.
 Hydrogen has quantized energy levels.
 Louis De Broglie’s wave-particle theory
 Heisenberg uncertainty principle
 The 4 Quantum numbers describe the properties of orbitals and predict the number of electrons in orbitals.
11.3 Atomic Orbitals
 The Bohr model assumed electrons travel around the nucleus in circular orbits which is incorrect.
 Schrodinger’s wave mechanical model assumes the electron has both particle and wave properties and describes
electrons as occupying orbitals.
1. The orbitals are different from the Bohr orbits.
2. Probability maps indicate the likelihood of finding the electron at a given point in space.
3. The size of an atom can be described by a surface that contains 90% of the total electron probability.
11.4 Electron Configurations and Atomic Properties
 Atomic energy levels are broken down into principal levels (n) which contain various numbers of sublevels.
1. The sublevels represent various types of orbitals (s, p, d, f) which have different shapes.
2. The number of sublevels increases as n increases.
 A given atom has Z protons in its nucleus and Z electrons surrounding the nucleus.
 The electrons occupy atomic orbitals starting with the lowest energy (Auf Bau principle)
 Hund’s rule describes the conditions of pairing electrons in an orbital.
 The Pauli Exclusion Principle states that an orbital can hold only two electrons with opposite spins.
 The electrons in the highest energy level are called valence electrons.
 Periodic trends: Atomic size – Ionization energy.
GR 12 CHEMISTRY MID YEAR EXAM STUDY GUIDE - Page 1 of 3
Make sure you check all the resources and worksheets in your binder:
• Textbook and the extra photocopied section.
• Chapter 11 class notes.
• Chapter 11 basic review worksheets.
• Chapter 11 team learning worksheets.
• Chapter 11 review (Modern Chemistry book).
• All Quizzes.
• All the work in Assignments section of your binder.
Chapter 6: Chemical Composition
Vocabulary:
Atomic mass unit
Avogadro’s number
Empirical formula
Average atomic mass
Molar mass
Molecular formula.
Mole
Mass percent
6.1 Atoms and Moles
 Objects do not need to have identical masses to be counted by weighing. All we need to know is the average mass of
the objects.
 To count the atoms in a sample of a given element by weighing we must know the mass of the sample and the average
mass for that element.

Samples in which the ratio of the masses is the same as the ratio of the masses of the individual atoms always contain
the same number of atoms.
 One mole of anything contains 6.022 X 1023 units of that substance.
 A sample of an element with a mass equal to that element’s average atomic mass (expressed in g) contains one mole of
atoms.
REMEMBER THE 2 TRIANGLES!!
6.2 Molar Mass and Percent Composition
 The molar mass of any compound is the mass in grams of one mole of the compound.
 The molar mass of a compound is the sum of the masses of the component atoms.
 Percent composition consists of the mass percent of each element in a compound:
Mass percent = molar mass of the element X 100
Molar mass of the compound
6.3 Formulas of Compounds
 The empirical formula of a compound is the simplest whole number ratio of the atoms present in the compound.
 The empirical formula can be found from the percent composition of the compound.
 The molecular formula is the exact formula of the molecules present in a substance.
 The molecular formula is always a whole number multiple of the empirical formula.
Make sure you check all the resources and worksheets in your binder:
 Chapter 6 class notes
 Chapter 6 team learning worksheets
 Sections 6.1 and 6.3 practice worksheets
 Chapter 6 standardized test practice
 All section reviews and chapter assessment questions
Chapter 9: Chemical Quantities
Vocabulary:
Mole ratio
Limiting reactant
Percent yield.
Stoichiometry
Theoretical yield
9.1 Using Chemical Equations
 A balanced chemical equation gives relative numbers (or moles) of reactant and product molecules that participate in a
chemical reaction.
 Stoichiometric calculations involve using a balanced chemical equation to determine the amounts of reactants needed
or products formed in a reaction.
 To convert between moles of reactants and moles of products, we use mole ratios derived from the balanced chemical
equation.
GR 12 CHEMISTRY MID YEAR EXAM STUDY GUIDE - Page 2 of 3
9.2 Using Chemical Equations to Calculate Mass
 To calculate masses from the moles of reactants needed or products formed, we can use the molar masses of
substances for finding the masses (g) needed or formed.
9.3 Limiting Reactants and Percent Yield
 Often, reactants in a chemical reaction are not present in stoichiometric quantities (they do not “run out” at the same
time).
• In this case, we must determine which reactant runs out first and thus limits the amount of products that can form—
this is called the limiting reactant.
 The actual yield (amount produced) of a reaction is usually less than the maximum expected (theoretical yield).
Percent yield = actual yield X 100
theoretical yield
Make sure you check all the resources and worksheets in your binder:
• Chapter 9 class notes
• Chapter 9 Practice worksheet
• Chapter 9 standardized test practice
• All section reviews and standardized test practice
Good Luck 
GR 12 CHEMISTRY MID YEAR EXAM STUDY GUIDE - Page 3 of 3