1. Naming and Formulas
Chapter 9

2. General Concepts Some Easy (English based)
Chemical Symbols - a universal shorthand used to identify the known elements on earth.
Ex. C H Fe
Rules for Chemical Symbols:
1. 1st letter capitalized
2. 2nd letter lowercase
Some Easy (English based)
Some Hard (Latin/Greek based)
He – helium
Al – aluminum
K – potassium (kalium)
Na – sodium (natrium)

3. Monoatomic Elements - most of the elements can exist alone & are written w/ no subscript.
Ex. Fe Ne C
Diatomic Elements/Molecules - there are seven elements that exist in nature
Exist with a subscript – a number to the right & slightly below a symbol that tells the number of atoms present
H2, N2, O2, F2, Cl2, Br2, I2

4. Chemical Formulas Ex. CO CO2 H2SO4
When elements combine, the newly formed compounds give both qualitative and quantitative information.
Qualitative -
Cannot be counted or measured
Ex. What elements are in the compound
Quantitative-
Can be counted or measured
Ex. # of atoms of each element that are present in the compound
Ex. CO CO2 H2SO4

5. Types of Formulas Simplest whole-number ratio Empirical Formula H2O
CH2O
CH4
Actual ratio of atoms in a molecule
Molecular Formula
H2O
C6H12O6
C2H8

6. Common Notations used in Equations
Symbol
Meaning +
Separates two reactants or products; say plus or and 
Separates reactant side from product side; say yields or produces
(s)
Substance in solid state
(l)
Liquid
(g)
Gas
(aq)
Aqueous

7. How do elements form compounds?
Atoms are electrically neutral (equal # of p+ and e-) however, they are not necessarily stable/happy.
Most atoms form ions when in solutions or combining with other atoms in a chemical reaction.
More with what ions are on the next slide
The ions that are formed are predictable… Using the periodic table.

8. You can determine the ions (oxidation states) from the PT.
Ions – atoms with either a positive or negative charge due to gaining or losing electrons
Cations – carry a positive charge (lost e-)
Generally metals Ex. Na1+
Anions – carry a negative charge (gain e-)
Generally nonmetals Ex. Si4-
You can determine the ions (oxidation states) from the PT.
Group Group Group Group 17

9. How do elements form compounds?
By the attraction of oppositely charged ions
Monatomic or polyatomic ions attract each other in a ratio that produces a neutral compound
Ex.
Sulfuric acid
Methane

10. Coefficients Coefficients – written in front of a formula.
Tells how many units of the formula are present; applies to the entire formula
Ex. 4H2O NH3 3C2H6
To determine the # of atoms present:
Consider the formula without the coefficient
Multiple each value by the coefficient to find the total of each type of atom.
Formula
Atoms
H2O
2 hydrogen
1 oxygen
4H2O
8 hydrogen
4 oxygen
Formula
Atoms
NH3
1 nitrogen
3 hydrogen
6NH3
6 nitrogen
18 hydrogen
Formula
Atoms
NH3
1 nitrogen
3 hydrogen
6NH3
6 nitrogen
18 hydrogen

11. How Do We Determine the Chemical Formula?
Steps:
Look up charges on PT
Balance positive and negative charges so that they = zero
Write formula using subscripts to tell how many of each element was used.
Ex. Calcium and Chlorine Ex. Aluminum and Oxygen

12. 9.1
Monatomic Ions
How are the charges of Group A metal and nonmetal ions related to their positions in the periodic table?
When the metals in Groups 1A, 2A, and 3A lose electrons, they form cations with positive charges equal to their group number.
Monatomic ions consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons, respectively.
The names of the cations of the Group 1A, Group 2A, and Group 3A metals are the same as the name of the metal, followed by the word ion or cation.

13. 9.1
Monatomic Ions
These elements have ionic charges that can be obtained from their group numbers.
The representative elements shown form positive ions with charges equal to their group numbers. Applying Concepts Are the ions anions or cations?

14. 9.1
Monatomic Ions
Anions
The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number.
Anion names start with the stem of the element name and end in -ide.
Ex. Fluoride Chloride Sulfide
Bromide Iodide Nitride

15. Monatomic Ions 9.1 These Group A elements form anions.
Note the positions of the nonmetals and the metalloid, arsenic. These elements form anions. Common transition elements that form more than one ion are also shown. Applying Concepts Do the transition metals form anions or cations?

16. Ions of Transition Metals
9.1
Ions of Transition Metals
How are the charges of some transition metal ions determined?
The charges of the cations of many transition metal ions must be determined from the number of electrons lost.
Transition Metals – roman numeral tells the charge
Ex. Iron (III) ion = Fe3+

17. Naming 9.1 1.) The Stock system 2.) The classical method
Two methods are used to name the ions of transition metals.
1.) The Stock system
2.) The classical method

18. Note that mercury (Hg) is a transition metal
Stock System
In the Stock system, a Roman numeral in parentheses is placed after the name of the element to indicate the numerical value of the charge.
Ex.
Mercury (II) oxide
Mercury (I) oxide
Mercury (II) chloride
Mercury (I) chloride
Note that mercury (Hg) is a transition metal

19. -ic is used with the higher of the two ionic charges
Classical Method
In an older less, useful method, the classical name of the element is used to form the root name for the element.
With different suffixes on the end
Ex. Iron
ferrum is Latin for iron ferr- is the root name for iron
-ous is the suffix used to name the cation with the lower of the two ionic charges
-ic is used with the higher of the two ionic charges
Fe2+
Fe3+
Iron(II) ion
Ferrous ion
Iron(III) ion
Ferric ion

20. 9.1
Monatomic Ions

21. Practice Write the symbol for the ion formed by each element.
Potassium
Iodide
Sulfur
Lead, 4 electrons lost
K+ : cation, potassium ion
I- : anion, iodide ion
S2-: anion, sulfide ion
Pb4+: cation, lead(IV) or plumbic ion

22. 9.1
Polyatomic Ions
What are the two endings of the names of most polyatomic ions?
Polyatomic ions – a group of atoms bonded together that carry a charge (See RT p.1 Table E)
Ex. OH- NO3- SO4-2
Some ions, called polyatomic ions, are composed of more than one atom.
The names of most polyatomic anions end in -ite or -ate.

23. 9.1
Polyatomic Ions
These models show the structures of four common polyatomic ions.
These molecular models show the arrangement of atoms in four common polyatomic ions. Interpreting Diagrams How does the ammonium ion differ from the other three?

24. Were You Paying Attention?
1.When metals from groups 1A, 2A, and 3A form cations, the charge on the ion is equal to
8 minus the group number.
the group number minus 8.
the period number.
the group number.

25. Were You Paying Attention?
2. Which of the following are positively charged polyatomic ions?
(I) ammonium ion
(II) perchlorate ion
(III) ferric ion
I only
II only
III only
I and III

26. Were You Paying Attention?
3. If the name of an ion ends in -ite or -ate, the ion is a
polyatomic cation.
polyatomic anion.
transition metal cation.
monatomic anion.

27. Binary Ionic Compounds
Essential Questions:
How are the names of binary ionic compounds determined?
How do you write the formulas for binary ionic compounds?

28. Naming Binary Ionic Compounds
9.2
Naming Binary Ionic Compounds
A binary compound is composed of two elements and can be either ionic or molecular.
Do Not Modify
Compound Formula:
KCl MgS AlN
Modify to end in -ide
Compound Name:
Potassium Magnesium Aluminum
chloride sulfide nitride
To name any binary ionic compound, place the cation name first, followed by the anion name.
Ex. Tin(II) sulfide Sn2+F1- SnF2
Sodium nitrate Na1+NO31- NaNO3

29. Writing Formulas for Binary Ionic Compounds
Write the symbol of the cation and then the anion. Add whatever subscripts are needed to balance the charges.
Balance the formula using appropriate subscripts:
Ion Formula:
Mg2+ Cl-
Ca2+ OH-
Compound Formula:
MgCl2
Ca(OH)2

30. Practice Write formulas for these binary ionic compounds:
a.) beryllium chloride
b.) potassium iodide
c.) calcium oxide

31. Practice Name each of the following binary ionic compounds: a.) NaBr
b.)AlF3
c.) MgS

32. Compounds With Polyatomic Ions
9.2
Compounds With Polyatomic Ions
How do you write the formulas and names of compounds containing polyatomic ions?
Write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges.
Ex. calcium nitrate
calcium cation polyatomic nitrate anion (Ca2+) (NO3–)
two nitrate anions, each with a 1– charge, are needed to balance the 2+ charge of each calcium cation.
The formula for calcium nitrate is Ca(NO3)2.

33. Writing Formulas for Compounds with Polyatomic Ions
Write the formula for each ion in the order listed in the name.
Use subscripts to balance the charges.
If more than one polyatomic ion is needed to balance a formula, place the polyatomic ion formula in parentheses, followed by a subscript showing the number needed.
Ex. Magnesium Hydroxide, aka Milk of magnesia

34. Practice Write formulas for these compounds: a.) tin(II) hydroxide
b.) lead(II) nitrate
c.) sodium phosphate

35. Naming Compounds with Polyatomic Ions
To name a compound containing a polyatomic ion, state the cation first and then the anion, just as you did in naming binary ionic compounds.
Ex. NaClO  Na+ ClO-  sodium hypochlorite

36. Practice Write names for each of the following compounds: a.) Sn(OH)2
b.) Ca(NO3)2
c.) K2CrO4

37. Were You Paying Attention?
1. The correct name for CrCl3 is
chromium chlorine.
chromium(III) chloride.
monochromium trichloride.
chromium(III) trichloride.

38. Were You Paying Attention?
2. What is the correct formula for strontium nitride?
Sr3N2
SrN2
Sr2N3
Sr3N

39. Were You Paying Attention?
3. Which one of the following compounds is named correctly?
sodium chlorite, NaClO
potassium nitrate, KNO2
sodium acetate, NaC2H3O2
lithium sulfate, Li2SO3

40. Naming and Writing Formulas for Molecular Compounds
9.3
Naming and Writing Formulas for Molecular Compounds
One milligram of gold is worth only about one cent, but one kilogram of gold is worth approximately $12,500. The correct prefix ( milli- or kilo-) makes quite a difference! Prefixes are important in chemistry, too. The prefixes in the name of a binary molecular compound tell you its composition.

41. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
What does a prefix in the name of a binary molecular compound tell you about the compound’s composition?
A prefix in the name of a binary molecular compound tells how many atoms of an element are present in each molecule of the compound.

42. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Some guidelines for naming binary molecular compounds:
Name the elements in the order listed in the formula.
Use prefixes to indicate the number of each kind of atom.
Omit the prefix mono- when the formula contains only one atom of the first element in the name.
The suffix of the name of the second element is -ide.

43. Writing Formulas for Binary Molecular Compounds
9.3
Writing Formulas for Binary Molecular Compounds
How do you write the formula for a binary molecular compound?
Use the prefixes in the name to tell you the subscript of each element in the formula. Then write the correct symbols for the two elements with the appropriate subscripts.

44. Practice Name each of the following binary molecular compounds:
a.) O2F2 d.) SF2
b.)SiF4 e.) H2S
c.)S4N4 f.) P4O10
Sulfur difluoride
Dioxygen difluroide
Silicon tetrafluoride
dihydrogen sulfide
Tetrasulfur tetranitride
Tetraphosphorous decaoxide

45. Naming Acids 9.4 What are the three rules for naming acids?
What are acids?
An acid is a compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water. Acids have various uses.

46. 9.4
Naming Acids
Three rules can help you name an acid with the general formula HnX.
RULE #1
When the name of the anion (X) ends in -ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix -ic and is followed by the word acid.
Ex. HCl(aq) Anion: Cl-1 = chloride  Hydrochloric acid
Practice:
H2S(aq)
Anion: S-2 = sulfide  Hydrosulfuric acid

47. 9.4
Naming Acids
RULE #2
When the anion name ends in -ite, the acid name is the stem of the anion with the suffix -ous, followed by the word acid.
Ex. H2SO3(aq) Anion: SO3 = sulfite  Sulfurous acid
Practice:
HNO2(aq)
HClO2
Anion: NO2 = nitrite  nitrous acid
Anion: ClO2 = chlorite  chlorous acid

48. 9.4
Naming Acids
RULE #3
When the anion name ends in -ate, the acid name is the stem of the anion with the suffix -ic followed by the word acid.
Ex. HNO3(aq) Anion: NO3 = nitrate  nitric acid
Practice:
H2SO4
H2CO3
Anion: SO4 = sulfate  sulfuric acid
Anion: CO3 = carbonate  carbonic acid

49. 9.4
Naming Acids
A Summary of the Three Rules for Naming Acids.

50. Writing Formulas for Acids
9.4
Writing Formulas for Acids
How are the formulas of acids determined?
Use the rules for writing the names of acids in reverse to write the formulas for acids.
What is the formula for hydrobromic acid? Following Rule 1, hydrobromic acid (hydro- prefix and -ic suffix) must be a combination of hydrogen ion (H+) and bromide ion (Br–). The formula of hydrobromic acid is HBr.

51. Writing Formulas for Acids
9.4
Writing Formulas for Acids

52. Names and Formulas for Bases
9.4
Names and Formulas for Bases
How are bases named?
Bases are named in the same way as other ionic compounds—the name of the cation is followed by the name of the anion.
For example, aluminum hydroxide consists of the aluminum cation (Al3+) and the hydroxide anion (OH–). The formula for aluminum hydroxide is Al(OH)3.

53. Were You Paying Attention?
1. The name for H2S(aq) is
sulfuric acid.
hydrosulfuric acid.
sulfurous acid.
hydrosulfurous acid.

54. Were You Paying Attention?
2. The chemical formula for chlorous acid is
HClO2.
HClO3.
HClO4.
HCl.

55. Were You Paying Attention?
3. The correct chemical name for NH4OH is
nitrogen tetrahydrogen hydroxide.
nitrogen pentahydrogen oxide.
ammonium oxyhydride.
ammonium hydroxide.

56. The Laws Governing Formulas and Names
9.5
The Laws Governing Formulas and Names
A birthday cake for a four-year-old has four candles. The ratio of candles to birthday cake is 4:1. In chemistry, similar relationships exist among the masses
of elements as they
combine in compounds.

57. The Laws of Definite and Multiple Proportions
9.5
The Laws of Definite and Multiple Proportions
What are the two laws that describe how compounds form?
The rules for naming and writing formulas for compounds are possible only because compounds form from the elements in predictable ways.
These ways are summed up in two laws: the law of definite proportions and the law of multiple proportions.

58. The Laws of Definite and Multiple Proportions
9.5
The Laws of Definite and Multiple Proportions
The law of definite proportions states that in samples of any chemical compound, the masses of the elements are always in the same proportions.
Water obeys the law of definite proportions. In every sample of water, the mass ratio of oxygen to hydrogen is always 8:1.
Mass of Oxygen = 16
Mass of Hydrogen = 2

59. The Laws of Definite and Multiple Proportions
9.5
The Laws of Definite and Multiple Proportions
The law of multiple proportions: Whenever the same 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.

60. The Laws of Definite and Multiple Proportions
9.5
The Laws of Definite and Multiple Proportions
A Diagram of the Law of Multiple Proportions
The diagram illustrates the law of multiple proportions. Two compounds, X and Y, contain equal masses of element B. The ratio of the masses of A in these compounds is 5:10 or 1:2 (a small whole number ratio). Applying Concepts Would the ratio be different if

61. Practicing Skills: Naming Chemical Compounds
9.5
Practicing Skills: Naming Chemical Compounds
How do you use a flowchart to write the name of a chemical compound?
Follow the arrows and answer the questions on the flowchart to write the correct name for a compound.

62. Practicing Skills: Naming Chemical Compounds
9.5
Practicing Skills: Naming Chemical Compounds
This flowchart will help you name chemical compounds. Begin with the letters Q and R in the general formula Qx Ry. Q and R can be atoms, monatomic ions, or polyatomic ions.

63. Practicing Skills: Naming Chemical Compounds
9.5
Practicing Skills: Naming Chemical Compounds
CuSO4 is an example from the flowchart. The compound will end in -ite or -ate. Cu is not part of Group A, so you must name the ions and use a Roman numeral to identify the charge of the transition metal. The name is copper(II) sulfate.
Blue copper(II) sulfate contains water in its crystal structure. When it is heated, it loses water and turns white. When the white solid absorbs water, it turns blue again.

64. Practicing Skills: Naming Chemical Compounds
9.4
Practicing Skills: Naming Chemical Compounds
What four guidelines should you follow to write the formula of a chemical compound?

65. Practicing Skills: Naming Chemical Compounds
9.5
Practicing Skills: Naming Chemical Compounds
In writing a chemical formula from a chemical name, it is helpful to remember the following guidelines.
An -ide ending generally indicates a binary compound.
An -ite or -ate ending means a polyatomic ion that includes oxygen is in the formula.
Prefixes in a name generally indicate that the compound is molecular.
A Roman numeral after the name of a cation shows the ionic charge of the cation.

66. Practicing Skills: Naming Chemical Compounds
9.5
Practicing Skills: Naming Chemical Compounds
This flowchart will help you write a chemical formula when given a chemical name. Interpreting Illustrations What are the two types of chemical compounds whose formulas you can write using this flowchart?

67. Were You Paying Attention?
1. The law of definite proportions states that in samples of any chemical compound, the elements are always in the same proportion by
mass.
volume.
group number.
period number.

68. Were You Paying Attention?
2. You want to write the chemical formula for iron(II) chloride. Based on Figure 9.22, after identifying symbols, what is the correct next step in the flowchart?
Group A elements
Roman numerals
Balance charges
Polyatomic ions

69. Were You Paying Attention?
3. Using the flowchart in Figure 9.20, if you determine that the name of an ion ends in -ite or -ate, the ion is a
polyatomic cation.
polyatomic anion.
transition metal cation.
group A anion.

70. Practice Problems
Solid iron is added to aqueous copper sulfate to yield aqueous iron sulfate and solid copper.
Solid magnesium metal reacts with aqueous hydrochloric acid to produce aqueous magnesium chloride and hydrogen gas.