1. Chapter 2 Atoms, Molecules, and Ions
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Chapter 2 Atoms, Molecules, and Ions
Copyright © 2011 Pearson Prentice Hall, Inc.

2. Compounds and Mixtures
Chapter 2: Atoms, Molecules, and Ions
5/13/2019
Compounds and Mixtures
Different compositions
Same compositions
The same number of protons
Cannot be separated physically
Variable
properties
Similar
properties
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3. Molecules and Covalent Bonds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Molecules and Covalent Bonds
Covalent Bond: Results when two atoms share several (usually two) electrons. Typically a nonmetal bonded to a nonmetal
Molecule: The unit of matter that results when two or more atoms are joined by covalent bonds.
Copyright © 2011 Pearson Prentice Hall, Inc.

4. Molecules and Covalent Bonds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Molecules and Covalent Bonds
Insert Figure 2.12 p56
Copyright © 2011 Pearson Prentice Hall, Inc.

5. Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Ions and Ionic Bonds
Ionic Bond: A transfer of one or more electrons from one atom to another. A strong electrical attraction between charged particles. Typically a metal bonded to a nonmetal.
Ion: A charged particle
Cation: A positively charged particle. Metals tend to form cations.
Anion: A negatively charged particle. Nonmetals tend to form anions.
Copyright © 2011 Pearson Prentice Hall, Inc.

6. Molecules, Ions, and Chemical Bonds
Chapter 2: Atoms, Molecules, and Ions
5/13/2019
Molecules, Ions, and Chemical Bonds
In the formation of sodium chloride, one electron is transferred from the sodium atom to the chlorine atom.
11 protons
11 electrons
17 protons
17 electrons
Na Cl1-
Na Cl
Sodium- very reactive in water!
Chlorine gas- can kill someone (Fritz Haber, WWI).
Sodium chloride- preservative, common food additive.
11 protons
10 electrons
17 protons
18 electrons
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7. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Naming Chemical Compounds
Cation Charges for Typical Main-Group Ions 1+ 2+ 3+
Metals tend to form cations. Note some in 3A and 4A with multiple charges.
Copyright © 2011 Pearson Prentice Hall, Inc.

8. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
Naming Chemical Compounds
5/13/2019 7:36:14 PM
Anion Charges for Typical Main-Group Ions 3- 2- 1-
Nonmetals tend to form anions. Noble gases do not naturally form ions in this sense.
Copyright © 2011 Pearson Prentice Hall, Inc.

9. Naming Ionic Compounds
To name a compound that contains two elements,
identify the cation and anion.
name the cation first, followed by the name of the anion with an –ide ending.

10. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Naming Chemical Compounds
Ionic Compound: A neutral compound in which the total number of positive charges must equal the total number of negative charges.
Total positive charge = Total negative charge
Copyright © 2011 Pearson Prentice Hall, Inc.

11. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Naming Chemical Compounds
Use Roman numerals in parentheses to indicate the charge on metals that form more than one kind of cation.
Copyright © 2011 Pearson Prentice Hall, Inc.

12. Example
Write the formula and names of the following compounds: 1) K+ and Br- 2) Al3+ and O2- 3) Pb4+ and S2- 4) Cu2+ and F-

13. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Naming Chemical Compounds
Binary Molecular Compounds
Because nonmetals often combine with one another in different proportions to form different compounds, numerical prefixes are usually included in the names of binary molecular compounds.
Copyright © 2011 Pearson Prentice Hall, Inc.

14. Naming Chemical Compounds
Chapter 2: Atoms, Molecules, and Ions
5/13/2019
Naming Chemical Compounds
N2F4
The first element listed is more cationlike and takes the name of the element.
The second element listed is more anionlike and takes the name of the element with an “ide” modification to the ending.
The prefix is added to the front of each to indicate the number of each atom.
dinitrogen tetrafluoride
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15. Naming Chemical Compounds
Chapter 2: Atoms, Molecules, and Ions
5/13/2019
Naming Chemical Compounds
Binary Molecular Compounds
Whenever the prefix ends in “a” or “o” and the element name begins with a vowel, drop the “a” or “o” in the prefix.
N2O4
dinitrogen tetroxide
Whenever the prefix for the first element is “mono,” drop it.
CO2
carbon dioxide CO
carbon monoxide
Copyright © 2008 Pearson Prentice Hall, Inc.

16. Learning Check
Write the name of each covalent compound. P2O5 _____________________ SiCl4 _____________________ CCl4 _____________________ N2O _____________________

17. Naming Chemical Compounds
Chemistry: McMurry and Fay, 6th Edition
Chapter 2: Atoms, Molecules, and Ions
5/13/2019 7:36:14 PM
Naming Chemical Compounds
Memorize
these ions + those on the handout
Polyatomic ions are covalently bonded atoms with a net charge.
Copyright © 2011 Pearson Prentice Hall, Inc.

18. Learning Check Write formula and name of the following compounds:
A. Mg2+ and NO3-
B. Al3+ and BrO4-
C. Fe2+ and HSO4-
D. Ba2+ and PO33-

19. Examples
Write the correct formula for each. A. aluminum nitrate B. copper(II) nitrate C. iron(III) hydrogen sulfite D. tin(IV) hydroxide