1. Chapter 6 Chemical Names and Formulas
Charles Page High School
Dr. Stephen L. Cotton

2. Section 6.1 Introduction to Chemical Bonding
OBJECTIVES:
Distinguish between ionic and molecular compounds.

3. Section 6.1 Introduction to Chemical Bonding
OBJECTIVES:
Define cation and anion, and relate them to metal and nonmetal.

4. Molecules and Molecular Compounds
About 100 different elements
Millions of compounds from them
Naming is essential in chemistry
Noble gases, such as He and Ne
Isolated atoms- monatomic, they consist of single atoms

5. Molecules and Molecular Compounds
Molecule- smallest electrically neutral unit, still has properties of the substance
Made from only nonmetals
Can be from one element- O2
Can make a compound- CO2

6. Molecules and Molecular Compounds
Properties of molecular compounds
Low melting and boiling points
Usually gas or liquid
Composed of two or more nonmetals
O2, O3, H2O

7. Systematic Naming
There are too many compounds to remember the names of them all.
Compound is made of two or more elements.
Put together atoms.
Name should tell us how many and what type of atoms.

8. Atoms and ions Atoms are electrically neutral.
Same number of protons and electrons.
Ions are atoms, or groups of atoms, with a charge (positive or negative)
Different numbers of protons and electrons.
Only electrons can move.
Gain or lose electrons.

9. F1- O2- Anion A negative ion. Has gained electrons.
Nonmetals can gain electrons.
Charge is written as a superscript on the right.
Has gained one electron (-ide is new ending= fluoride)
F1-
O2-
Gained two electrons (oxide)

10. K1+ Ca2+ Cations Positive ions. Formed by losing electrons.
More protons than electrons.
Metals can lose electrons
K1+
Has lost one electron (no name change for positive ions)
Ca2+
Has lost two electrons

11. Ionic Compounds
Ionic compounds- from joining metal cations and nonmetal anions- they are electrically neutral
Usually solid crystals
Melt at high temperatures

12. Two Types of Compounds Molecular compounds Made of molecules.
Made by joining nonmetal atoms together into molecules.

13. Two Types of Compounds Ionic Compounds Made of cations and anions.
Metals and nonmetals.
The electrons lost by the cation are gained by the anion.
The cation and anions surround each other.
Smallest piece is a FORMULA UNIT.

14. Two Types of Compounds Ionic Molecular Smallest piece Formula Unit
Molecule
Types of elements
Metal and Nonmetal
Nonmetals
Solid, liquid or gas
State
solid
Melting Point
High >300ºC
Low <300ºC

15. Section 6.2 Representing Chemical Compounds
OBJECTIVES:
Distinguish among chemical formulas, molecular formulas, and formula units.

16. Section 6.2 Representing Chemical Compounds
OBJECTIVES:
Use experimental data to show that a compound obeys the law of definite proportions.

17. Chemical Formulas
Shows the kind and number of atoms in the smallest piece of a substance.
Molecular formula- number and kinds of atoms in a molecule.
CO2
C6H12O6

18. Chemical Formulas More than one atom? –use a subscript (H2O)
There are 7 diatomic elements
Hydrogen (H2), Nitrogen (N2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), and Iodine (I2)
Remember: “Br I N Cl H O F”

19. Ionic Compounds
This formula represents not a molecule, but a formula unit
The smallest whole number ratio of atoms in an ionic compound.
Ions surround each other so you can’t say which is hooked to which. (p. 140)

20. Some Laws:
1. Law of Definite Proportions- in a sample of a chemical compound, the masses of the elements are always in the same proportions.
H2O (water) and H2O2 (hydrogen peroxide)

21. Some Laws:
2. Law of Multiple Proportions- Dalton stated that whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.
Figure 6.11, p. 141

22. Section 6.3 Ionic Charges OBJECTIVES:
Use the periodic table to determine the charge on an ion.

23. Section 6.3 Ionic Charges OBJECTIVES:
Define a polyatomic ion, and give the names and formulas of the most common polyatomic ions.

24. Charges on ions
For most of the Group A elements, the Periodic Table can tell what kind of ion they will form from their location; monatomic ions
Elements in the same group have similar properties.
Including the charge when they are ions.

25. 1+ 2+ 3+ 3- 2- 1-