Transcript Chapter 2 PPT - AP - Westminster Public Schools

AP*
Chapter 2
Atoms, Molecules,
and Ions
AP Learning Objectives
 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)
Section 2.2
Fundamental Chemical Laws
AP Learning Objectives, Margin Notes and References
 Learning Objectives


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")
Section 2.2
Fundamental Chemical Laws
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.
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Section 2.2
Fundamental Chemical Laws
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.
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Section 2.3
Dalton’s Atomic Theory
AP Learning Objectives, Margin Notes and References
 Learning Objectives

LO 1.17 The student is able to express the law of conservation of mass quantitatively and qualitatively using
symbolic representations and particulate drawings.
Section 2.3
Dalton’s Atomic Theory
Dalton’s Atomic Theory (1808)

Each element is made up of tiny particles called atoms.
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Section 2.3
Dalton’s Atomic Theory
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.
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Section 2.3
Dalton’s Atomic Theory
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.
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Section 2.3
Dalton’s Atomic Theory
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.
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Section 2.3
Dalton’s Atomic Theory
Gay-Lussac and Avogadro (1809—1811)

Gay—Lussac
 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.
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Section 2.3
Dalton’s Atomic Theory
Representing Gay—Lussac’s Results
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Section 2.3
Dalton’s Atomic Theory
Representing Gay—Lussac’s Results
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Section 2.3
Dalton’s Atomic Theory
Representing Gay—Lussac’s Results
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Section 2.3
Dalton’s Atomic Theory
Representing Gay—Lussac’s Results
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Section 2.6
Molecules and Ions
AP Learning Objectives, Margin Notes and References
 Learning Objectives

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.
Section 2.6
Molecules and Ions
Chemical Bonds

Covalent Bonds
 Bonds form between atoms by sharing electrons.
 Resulting collection of atoms is called a molecule.
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Section 2.6
Molecules and Ions
Covalent Bonding
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Section 2.6
Molecules and Ions
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).
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Section 2.6
Molecules and Ions
Molecular vs Ionic Compounds
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Section 2.6
Molecules and Ions
EXERCISE!
A certain isotope X+ contains 54 electrons and 78
neutrons.
 What is the mass number of this isotope?
133
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Section 2.6
Molecules and Ions
CONCEPT CHECK!
Which of the following statements regarding Dalton’s
atomic theory are still believed to be true?
I. Elements are made of tiny particles called atoms.
II. All atoms of a given element are identical.
III. A given compound always has the same relative
numbers and types of atoms.
IV. Atoms are indestructible.
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Section 2.7
An Introduction to the Periodic Table
AP Learning Objectives, Margin Notes and References
 Learning Objectives

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.
Section 2.7
An Introduction to the Periodic Table
The Periodic Table



Metals vs. Nonmetals
Groups or Families – elements in the same vertical
columns; have similar chemical properties
Periods – horizontal rows of elements
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Section 2.7
An Introduction to the Periodic Table
The Periodic
Table
Section 2.7
An Introduction to the Periodic Table
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)
0
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