1. Chemical Names and Formulas
6.1 Introduction to Chemical Bonding
6.2 Representing Chemical Compounds
6.3 Ionic Charges
6.4 Ionic Compounds
6.5 Molecular Compounds and Acids
6.6 Naming and Formula Writing

2. 6.1 Objectives Distinguish between ionic and molecular compounds
Define cation and anion, relate them to metal and non- metal
metal/cation
nonMetal/anion

3. 6.1 Vocabulary Molecule Molecular compound Ions Cations Anions
Ionic compounds

4. Introduction to Chemical Bonding
Molecules and Molecular Compounds
Tend to have low boiling and melting points
May be gases or liquids at room temperature (RT)
Are composed of non-metals, CO2
Ions and Ionic Compounds, (+) and (-)
Have balanced charges, 2(+) must have 2(-)
Have high boiling and melting points, (solid at RT)
Are composed of metals and non-metals (combined)

5. Ions: Symbols and Names
Cations: these are metals that lose electrons
When you lose a (-) you become more positive
If Potassium (K) loses 1 electron it becomes K+1
Example: (19+ and 19–) changes to (19+ and 18-)
Anions: these are nonMetals that gain electrons
When you gain a (-) you become more negative
If Bromine (Br) gains one electron it becomes Br-1
Example: (35+ and 35-) changes to (35+ and 36-)
Anions change their suffix to –ide, (Bromine to Bromide)

7. Characteristics of Compounds
Molecular Compound
Ionic Compound
Representative Unit
Molecule
Formula Unit
Type of Elements
nonMetals
Metal and nonMetal
Physical State
Solid, liquid , or Gas
Solid
Melting Point
Low, (below 300 C)
High, (above 300C)

8. Questions
What is the symbol and name for an Oxygen atom that has gained two electrons?
O2- and Oxide
What is the symbol and name for an Iron atom that has lost two electrons?
Fe2+ and Iron (II)

9. Definitions
A Molecule is the smallest electrically neutral unit of a substance
A Molecular compound are combinations of atoms
Ions are charged atoms or molecules
Cations are positively charged (+)
Anions are negatively charged (-)
Ionic compounds combine the (+) and (-)

10. 6.2 Objectives
Distinguish among chemical formulas, molecular formulas, and formula units
Use experimental data to show that a compound obeys the law of definite proportions

11. Vocabulary Chemical formula Molecular formula Formula unit
Law of Definite Proportions
Law of Multiple Proportions

12. Formula Unit is a crystal

13. HONClBrIF Diatomic Molecules, (exist as two bonded atoms)
(H) Hydrogen as H2
(O) Oxygen as O2
(N) Nitrogen as N2
(Cl) Chlorine as Cl2
(Br) Bromine as Br2
(I) Iodine as I2
(F) Fluorine as F2

14. Counting Atoms and Assigning Mass
When elements react to form compounds, they react in defined, whole-number ratios. The experiments that Dalton and others performed showed that reactions are not random events; they proceed according to precise and well-defined formulas.

15. Water, for example, is always made up of two parts hydrogen and one part oxygen. The chemical formula of a compound is written by listing the symbols of the elements together, without any spaces between them. If a molecule contains more than one atom of an element, a number is subscripted after the symbol to show the number of atoms of that element in the molecule. Thus the formula for water is H2O, never HO or H2O2.

16. Questions How are the images different?
In every sample of Carbon Monoxide the mass ratio is 3:4 for the mass of Carbon : Oxygen.
In sample 1: Carbon is 9 grams and Oxygen is ____
In sample 2: Carbon is _____and Oxygen is 8 grams

17. Definitions
A Chemical formula shows the kind and number of atoms in a representative unit
A Molecular formula shows the kind and number of atoms in a molecule
A Formula unit is the lowest whole number ratio in a compound, when ions come together to form a crystal
Law of Definite Proportions: the masses of the elements in a compound always conform to a ratio
Law of Multiple Proportions: different compounds may have different ratios of the same elements

18. 6.3 Objectives
Use the Periodic Table to determine the charge of an ion
Define a polyatomic ion
Name the most common examples of polyatomic ions

19. Vocabulary
Monoatomic ions
Polyatomic ions

20. The Mono-Atomic Ions
See the table on page 143 for the Representative Elements
See the table on page 144 for some Transition Metal Elements

21. Some Transition Metal Ions
Complexes may be quite colorful
The paint industry uses transition metal ions to provide color

22. Poly-Atomic Ions Ammonium ion is positive (+)
Nitrate ion is negative (-)
In each case there are multiple atoms acting as a tightly bound unit
The table on page 147 provides a good list

23. Questions
What is the charge on a Potassium atom that has changed to an ion?
What is the charge of a Bromine atom that has changed to an ion?
Using page 147, what is the charge of Sulfite?
What is the charge of Iron (III)?
How would you write an ion of Cobalt (II)?
What is the name of Sn+4 ?

24. Definitions Monoatomic ions are ions consisting of only one atom
Cation: Li+1
Anion: Br-1
Polyatomic ions are tightly bound groups of atoms that behave as a unit and carry a charge
Cation: NH4+1
Anion: Cr2O7-2

25. 6.4 Objectives
Apply the rules for naming and writing formulas for binary compounds
Apply the rules for naming and writing the formulas for ternary ionic compounds

26. Vocabulary
Binary compounds
Ternary compounds

27. How to write a chemical formula
Start by identifying the types of atoms
Hydrogen and Oxygen
Count the atoms of each type
Two H and One O leads to the formula H2O

28. Naming a binary ionic compound
Determine the positive ion, in this case Sodium+
Determine the negative ion, in this case Chlorine-
Determine the charges (+) and (-), both are 1
The positive (cation) is first, then the anion
Sodium Chloride is NaCl and has no charge

29. Naming a ternary ionic compound
Notice the green ball, (Mg+2), and the ball that is red/white, (OH-), the ratio is 1:2 or Mg(OH)2
Magnesium Hydroxide

30. Definitions Binary compounds are composed of two elements
NaCl
Ternary compounds are composed of three different elements
CaCO3

31. 6.5 Objectives
Apply the rules for naming and writing formulas for binary molecular compounds
Name and write formulas for common acids

32. Binary molecular compounds
Prefixes for naming binary molecular:
mono- 1 di- 2 tri- 3 tetra- 4 penta- 5
hexa- 6 hepta- 7 octa-8 nona- 9 deca- 10
- diNitrogen tetraHydride, (N2H4)

33. Naming common acids (aq) means it is in water
Acids break apart in water
Six acids are commonly used, (see the chart at left)
There are rules for naming acids, (hydro- and –ic acids)

34. 6.6 Objectives
Use the flowchart in Fig to write the name of a compound when given its chemical formula
Use the flowchart in Fig to write a chemical formula of a compound when given its name