2. LO 1.1 The student can justify the observation that the ratio of the masses of the constituent elements in any pure sample of that compound is always identical on the basis of the atomic molecular theory. (Sec 2.2)
LO 1.17 The student is able to express the law of conservation of mass quantitatively and qualitatively using symbolic representations and particulate drawings. (Sec 2.2, 2.3)
LO 2.17 The student can predict the type of bonding present between two atoms in a binary compound based on position in the periodic table and the electronegativity of the elements. (Sec 2.6, 2.7)
LO 3.5 The student is able to design a plan in order to collect data on the synthesis or decomposition of a compound to confirm the conservation of matter and the law of definite proportions. (Sec 2.2)
LO 3.6 The student is able to use data from synthesis or decomposition of a compound to confirm the conservation of matter and the law of definite proportions. (Sec 2.2)

3. AP Learning Objectives, Margin Notes and References
LO 1.1 The student can justify the observation that the ratio of the masses of the constituent elements in any pure sample of that compound is always identical on the basis of the atomic molecular theory.
LO 1.17 The student is able to express the law of conservation of mass quantitatively and qualitatively using symbolic representations and particulate drawings.
Additional AP References
LO 3.5 (see APEC Lab 7, " Hydrates and Thermal Decomposition")
LO 3.6 (see APEC Lab 7, " Hydrates and Thermal Decomposition")

4. Three Important Laws Law of conservation of mass (Lavoisier):
Mass is neither created nor destroyed in a chemical reaction.
Law of definite proportion (Proust):
A given compound always contains exactly the same proportion of elements by mass.

5. Three Important Laws (continued)
Law of multiple proportions (Dalton):
When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers.

6. AP Learning Objectives, Margin Notes and References
LO 1.17 The student is able to express the law of conservation of mass quantitatively and qualitatively using symbolic representations and particulate drawings.

7. Dalton’s Atomic Theory (1808)
Each element is made up of tiny particles called atoms.

8. Dalton’s Atomic Theory (continued)
The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.

9. Dalton’s Atomic Theory (continued)
Chemical compounds are formed when atoms of different elements combine with each other. A given compound always has the same relative numbers and types of atoms.

10. Dalton’s Atomic Theory (continued)
Chemical reactions involve reorganization of the atoms—changes in the way they are bound together.
The atoms themselves are not changed in a chemical reaction.

11. Gay-Lussac and Avogadro (1809—1811)
Measured (under same conditions of T and P) the volumes of gases that reacted with each other.
Avogadro’s Hypothesis
At the same T and P, equal volumes of different gases contain the same number of particles.
Volume of a gas is determined by the number, not the size, of molecules.

12. Representing Gay—Lussac’s Results

13. Representing Gay—Lussac’s Results

14. Representing Gay—Lussac’s Results

15. Representing Gay—Lussac’s Results

16. AP Learning Objectives, Margin Notes and References
LO 2.17 The student can predict the type of bonding present between two atoms in a binary compound based on position in the periodic table and the electronegativity of the elements.

17. Chemical Bonds Covalent Bonds
Bonds form between atoms by sharing electrons.
Resulting collection of atoms is called a molecule.

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19. Chemical Bonds Ionic Bonds
Bonds form due to force of attraction between oppositely charged ions.
Ion – atom or group of atoms that has a net positive or negative charge.
Cation – positive ion; lost electron(s).
Anion – negative ion; gained electron(s).

20. Molecular vs Ionic Compounds
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21. A certain isotope X+ contains 54 electrons and 78 neutrons.
EXERCISE!
A certain isotope X+ contains 54 electrons and 78 neutrons.
What is the mass number of this isotope?
133
The mass number is 133. The plus charge in X+ means that the ion has lost an electron, therefore the number of protons is 55 (54+1). The ion is Cs+ with a mass number of 133 (55+78).
Note: Use the red box animation to assist in explaining how to solve the problem.

22. CONCEPT CHECK!
Which of the following statements regarding Dalton’s atomic theory are still believed to be true?
Elements are made of tiny particles called atoms.
All atoms of a given element are identical.
A given compound always has the same relative
numbers and types of atoms.
IV. Atoms are indestructible.
Statements I and III are true. Statement II is not true (due to isotopes and ions). Statement IV is not true (due to nuclear chemistry).

23. AP Learning Objectives, Margin Notes and References
LO 2.17 The student can predict the type of bonding present between two atoms in a binary compound based on position in the periodic table and the electronegativity of the elements.

24. The Periodic Table Metals vs. Nonmetals
Groups or Families – elements in the same vertical columns; have similar chemical properties
Periods – horizontal rows of elements

25. The Periodic Table

26. Alkaline Earth Metals (2A)
Groups or Families
Table of common charges formed when creating ionic compounds.
Group or Family
Charge
Alkali Metals (1A) 1+
Alkaline Earth Metals (2A) 2+
Halogens (7A) 1–
Noble Gases (8A)