1. Chapter 7 Language of Chemistry by Christopher Hamaker
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Chapter 7

2. IUPAC
The International Union of Pure and Applied Chemistry, IUPAC, has set rules for naming compounds.
IUPAC set the rules for the naming and classification of inorganic compounds in 1940.
These rules, referred to as IUPAC nomenclature, are still in use today.
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Chapter 7

3. Classification of Compounds
Most inorganic compounds do not contain the element carbon.
The exceptions are carbon dioxide, CO2, and carbonates, which contain the ion CO32–.
There are five common classes of inorganic compounds:
Binary ionic
Ternary ionic
Binary molecular
Binary acid
Ternary oxyacid
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Chapter 7

4. Classification of Compounds, Continued
Below is a flow chart for the classification of inorganic compounds.
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Chapter 7

5. Principal Types of Chemical Bonds: Ionic and Covalent
Ionic bond - a transfer of one or more electrons from one atom to another.
forms attractions due to the opposite charges of the atoms.
Molecular (Covalent) bond - attractive force due to the sharing of electrons between atoms.

6. Example Video Ionic and covalent bonding animation (1:56 min)
Ionic, Covalent, and Metallic Bonds (13:22 min)
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Chapter 4

7. Chemical Formulas; Molecular and Ionic Substances
Although many substances are molecular, others are composed of ions.
An ion is an electrically charged particle obtained from an atom or chemically bonded group of atoms by adding or removing electrons.
Sodium chloride is a substance made up of ions. 2

8. Na+ is “isoelectronic” with Ne
Ion Formation and the Octet Rule
Metallic elements tend to form positively charged ions called cations.
Metals tend to lose all their valance electrons to obtain a configuration of the noble core. Na
Na+ + e-
[Ne]3s1
[Ne]
Na+ is “isoelectronic” with Ne

9. O + 2e- O2- [He]2s22p4 [He]2s22p6 or [Ne]
Isoelectronic - they have the same electron configuration (same number of electrons)
Nonmetallic elements tend to form negatively charged ions called anions.
Nonmetals tend to gain electrons so they become isoelectronic with its nearest noble gas neighbor. O
+ 2e-
O2-
[He]2s22p4
[He]2s22p6 or [Ne]

10. The ionic compound NaCl
ionic compounds consist of a combination of cations and an anions
the formula is always the same as the empirical formula
the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero
The ionic compound NaCl

11. Chemical Substances; Formulas and Names
Ionic compounds
Most ionic compounds contain metal and nonmetal atoms; for example, NaCl.
You name an ionic compound by giving the name of the cation followed by the name of the anion.
A monatomic ion is an ion formed from a single atom. 2

12. Ionic Compounds
Binary ionic compounds contain two elements: one metal and one nonmetal.
NaCl and AlCl3 are binary ionic compounds.
Ternary ionic compounds contain three elements, at least one metal and one nonmetal.
KNO3 and Al(NO3)3 are ternary ionic compounds.
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Chapter 7

13. Molecular compounds
nonmetals or nonmetals + metalloids
common names
H2O, NH3, CH4, C60

14. Molecular Compounds
Binary molecular compounds contain two elements and both are nonmetals.
Some examples of binary molecular compounds are ammonia, NH3; methane, CH4; carbon dioxide, CO2; and tetraphosphorous trisulfide, P4S3.
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Chapter 7

15. An acid can be defined as a substance that yields
hydrogen ions (H+) when dissolved in water.
HCl
Pure substance, hydrogen chloride
Dissolved in water (H+ Cl-), hydrochloric acid
An oxoacid is an acid that contains hydrogen, oxygen, and another element.
HNO3
nitric acid
H2CO3
carbonic acid
H2SO4
sulfuric acid
HNO3

16. Aqueous Acids
An aqueous solution is produced when a compound dissolves in water. It is indicated by the symbol (aq).
A binary acid is an aqueous solution of a compound containing hydrogen and one other nonmetal. HF (aq) is a binary acid.
A ternary oxyacid is an aqueous solution of a compound containing hydrogen, oxygen, and one other nonmetal. HNO3(aq) is a ternary oxyacid.
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Chapter 7

17. Classification of Ions
Recall, an ion is an atom or group of atoms with a charge.
A positively charged ion is called a cation.
A negatively charged ion is called an anion.
A group of atoms bound together that has an overall charge is called a polyatomic anion.
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Chapter 7

18. Chemical Substances; Formulas and Names
Polyatomic ions
A polyatomic ion is an ion consisting of two or more atoms chemically bonded together and carrying a net electric charge. 2

19. Classification of Ions, Continued
Below is a flow chart for the classification of ions.
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Chapter 7

20. cation – ion with a positive charge
An ion is an atom, or group of atoms, that has a net positive or negative charge.
cation – ion with a positive charge
If a neutral atom loses one or more electrons
it becomes a cation. Na
11 protons
11 electrons
Na+
11 protons
10 electrons
anion – ion with a negative charge
If a neutral atom gains one or more electrons
it becomes an anion.
Cl-
17 protons
18 electrons Cl
17 protons
17 electrons

21. Monoatomic Cations
Metal atoms can lose valence electrons and become positively charged cations.
Cations are named for the parent atom followed by the word “ion.”
Na+ is named “sodium ion.”
Al3+ is named “aluminum ion.”
This rule applies for metals that usually form one ion. This includes the main group metals except tin and lead, along with Ag+, Zn2+, and Cd2+.
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Chapter 7

22. Metals that Form Multiple Ions
If a metal can form more than one cation, it is named for the parent, followed by the charge in Roman numerals in parentheses, followed by the word “ion.”
Fe2+ is the iron(II) ion.
Fe3+ is the iron(III) ion.
This is called the Stock system of naming cations.
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Chapter 7

23. Monoatomic Anions
Nonmetals can gain valence electrons and become negatively charged anions.
Monoatomic anions are named by dropping the end of the element name and adding the suffix –ide.
Br- is the bromide ion.
O2- is the oxide ion.
N3- is the nitride ion.
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Chapter 7

24. Predicting Cation Charges
Recall that Group 1 metals always form +1 ions and Group 2 ions always form +2 ions.
We can predict that Group 13 ions will form ions.
Not all metal ion charges are predictable: tin and lead in Group 14 form both +2 and +4 ions.
Most transition metals form +2 ions from the loss of their two s electrons.
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Chapter 7

25. Predicting Anion Charges
Nonmetals gain electrons to form anions in a predictable fashion.
Group 17 atoms gain one electron to form –1 ions: F-, Cl-, Br-, and I-.
Group VIA/16 atoms gain two electrons to form –2 ions: O2-, S2-, Se2-, and Te2-.
Group VIA/15 atoms gain three electrons to form –3 ions: N3-, P3-, and As3-.
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Chapter 7

26. Ion Charges
Shown are the elements on the periodic table and their common charges.
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Chapter 7

27. A monatomic ion contains only one atom
Na+, Cl-, Ca2+, O2-, Al3+, N3-
A polyatomic ion contains more than one atom
OH-, CN-, NH4+, NO3-

28. Polyatomic Anions
Polyatomic anions generally contain one or more elements combined with oxygen. These anions are called oxyanions.
Most oxyanions have names that end in the suffix -ate.
SO42- is the sulfate ion.
NO3- is the nitrate ion.
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Chapter 7

29. Naming Oxyanions Some oxyanions end in the suffix -ite.
NO2- is the nitrite ion.
SO32- is the sulfite ion.
Notice that these oxyanions have one less oxygen: sulfate (SO42-) and nitrate (NO3-).
The oxyanions that end in -ite each have one less oxygen than the oxyanions that end in -ate.
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Chapter 7

30. More Polyatomic Anions
The formula for the chlorate ion is ClO3-. What is the formula for the chlorite ion?
The suffix has changed from -ate to -ite. Chlorite must have one less oxygen then chlorate, so its formula is ClO2-.
Notice that the charge does not change as the number of oxygen atoms changes.
There are two common polyatomic ions that end in -ide:
Hydroxide, OH-
Cyanide, CN-
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Chapter 7

31. Some Common Polyatomic Ions
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Chapter 7

32. Example Video What's a polyatomic ion? (5:15 min)
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Chapter 4

33. Let’s examine the formation of NaCl Na + Cl  NaCl
IONIC BONDING
Let’s examine the formation of NaCl
Na + Cl  NaCl
Chlorine has a high
electron affinity.
When chlorine gains
an electron, it gains
the Ar configuration.
Sodium has a
low ionization energy
it readily loses this
electron .
When Sodium loses
the electron, it gains
the Ne configuration.
Na  Na+ + e-

34. Essential Features of Ionic Bonding
Atoms with low I.E. and low E.A. tend to form positive ions.
Atoms with high I.E. and high E.A. tend to form negative ions.
Ion formation takes place by electron transfer.
The ions are held together by the electrostatic force of the opposite charges.
Reactions between metals and nonmetals (representative) tend to be ionic.

35. Writing Ionic Formulas
An ionic compound is composed of positive and negative ions.
A formula unit is the simplest representative particle of an ionic compound.
A formula unit is neutral, so the total positive charge must equal the total negative charge in the formula unit.
When writing chemical formulas, the cation (metal) goes first and the anion (nonmetal) goes second.
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Chapter 7

36. Formulas of Ionic Compounds
If the ions in the ionic compound have the same charge, the formula unit contains one of each ion.
Na+ and Cl- combine to form NaCl.
Mg2+ and S2- combine to form MgS.
If the charges are not equal, we must balance the positive and negative charges.
Ca2+ and Cl- combine to form CaCl2.
Na+ and O2- combine to form Na2O.
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Chapter 7

37. Crossover Rule
You can quickly verify that the chemical formula is written correctly by crossing over the charge on each ion.
The charge on the aluminum ion becomes the subscript for the oxygen, and the charge on the oxide ion becomes the subscript for the aluminum ion.
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Chapter 7

38. Formula of Ionic Compounds
2 x +3 = +6
3 x -2 = -6
Al2O3
Al3+
O2-
1 x +2 = +2
2 x -1 = -2
CaBr2
Ca2+
Br-
1 x +2 = +2
1 x -2 = -2
Na2CO3
Na+
CO32-

39. Formulas with Polyatomic Ions
Follow the same rules as binary ionic compounds; if the charges are equal, the formula has one of each ion.
Mg2+ and SO42- combine to form MgSO4.
K+ and ClO3- combine to form KClO3.
If the charges are not equal, total charge must equal zero. If you have more than one polyatomic ion, it is placed in parentheses.
Al3+ and CO32- combine to form Al2(CO3)2.
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Chapter 7

40. Polyatomic Ions You Should Know
NH4+ - Ammonium
OH- - Hydroxide
CN- - Cyanide
SO42- - Sulfate
ClO4- - Perchlorate
O22- - Peroxide
PO43- - Phosphate
CO32- - Carbonate
HCO3- - Hydrogen carbonate

41. Determining Ionic Charges
If an ionic compound contains a metal that can have more than one ionic charge, we must determine the charge on the ion. The sum total charge of an ionic compound must equal zero.
What is the charge on the chromium ion in Cr3N2?
The charge on a nitride ion is always –3, so we have a total of six negative charges (2 × N3- = 6 negative).
The sum of the charges on the chromium ions must be six positive.
Crx+ + Crx+ + Crx+ = 6 positive  Each Cr is 2+.
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Chapter 7

42. Naming Compounds and Writing Formulas of Compounds
Nomenclature - the assignment of a correct and unambiguous name to each and every chemical compound.

43. Chemical Nomenclature
Ionic Compounds
often a metal + nonmetal
anion (nonmetal), add “ide” to element name
BaCl2
barium chloride
K2O
potassium oxide
Mg(OH)2
magnesium hydroxide
KNO3
potassium nitrate

44. Let's Practice
Give the formula for the following ionic compounds:
1. sodium sulfide
2. copper(I) carbonate
3. magnesium phosphate
4. chromium(II) sulfate

45. Critical Thinking: Potassium
Potassium is an extremely reactive element (its violent reaction with water is pictured below).
How can such a reactive element (with water) be essential for human life?
The potassium ion (K+) is essential, not the free element.
Good sources of potassium include fish, meat, fruit, dark vegetables, and nuts.
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Chapter 7

46. Example Video Ionic Compounds: UPDATED - Chemistry Tutorial (7:18 min)
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Chapter 4

47. Naming Binary Ionic Compounds
When naming ionic compounds, we combine the cation and anion name (drop the word “ion”), with the cation first and the anion second.
MgO is composed of one magnesium ion and one oxide ion, therefore the name is magnesium oxide.
What is the name of cinnabar, HgS?
Hg2+ is the mercury(II) ion and S2- is the sulfide ion, so the name is mercury(II) sulfide.
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Chapter 7

48. A. Writing Formulas of Ionic Compounds
Determine the charge of the ions (usually can be obtained from the group number.)
Cations and anions must combine to give a formula with a net charge of zero
It must have the same number of positive charges as negative charges.

49. Naming Binary Compounds
NaF -
LiCl -
MgO -

50. Naming Binary Compounds
NaF - Sodium Fluoride
LiCl - Lithium Chloride
MgO - Magnesium Oxide

51. Predicting Formulas
Predict the formula of the ionic compounds formed from the following combination of ions:
1. sodium and sulfur
2. magnesium and oxygen
3. aluminum and oxygen
4. barium and fluorine

52. Formulas for Binary Ionic Compounds
We can determine formula of a binary ionic compound from its name.
What is the formula of iron(III) fluoride?
Iron(III) has a +3 charge, Fe3+; and fluoride has a –1 charge, F-.
Since the total charge must equal zero, the formula for iron(III) fluoride is FeF3.
+3 + 3(– 1) = zero
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Chapter 7

53. 1. Name cation followed by the name of anion.
B. Writing Names of Ionic Compounds from the Formula 2
Stock System:
1. Name cation followed by the name of anion.
2. Give anion the suffix -ide.
Examples:
NaCl is sodium chloride.
AlBr3 is aluminum bromide.

54. Roman numeral gives the charge of the metal.
If the cation of an element has several ions of different charges (as with Transition metals) use a Roman numeral after the metal name.
Roman numeral gives the charge of the metal.
Examples:
FeCl3 is iron(III) chloride
FeCl2 is iron(II) chloride
CuO is copper(II) oxide

55. Transition metal ionic compounds
indicate charge on metal with Roman numerals
FeCl2
iron(II) chloride
2 Cl- -2 so Fe is +2
FeCl3
3 Cl- -3 so Fe is +3
iron(III) chloride
Cr2S3
3 S-2 -6 so Cr is +3 (6/2)
chromium(III) sulfide

56. Common Nomenclature System
Use -ic to indicate the higher of the charges.
Use -ous to indicate the lower of the charges.
Examples:
FeCl2 is ferrous chloride
FeCl3 is ferric chloride
Cu2O is cuprous oxide
CuO is cupric oxide

57. Naming Ternary Ionic Compounds
We name ternary ionic compounds like binary ionic compounds: the cation name followed by the anion name.
K2CO3 is named potassium carbonate.
If we have a metal that can have than one oxidation state, we have to determine the charge on the metal.
Co(ClO3)3 is composed of cobalt(III) and chlorate ions, so its name is cobalt(III) chlorate.
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Chapter 7

58. Formulas for Binary Compounds
We can predict the formula of an ionic compound based on the formula of a similar compound.
What is the formula of radium carbonate given that calcium carbonate is CaCO3?
Radium, Ra, and calcium are both in Group 2 and will have the same ionic charge.
The formula for radium carbonate is RaCO3.
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Chapter 7

60. Binary Molecular Compounds
Binary molecular compounds are composed of two nonmetal elements.
A molecule is the simplest representative particle of a binary molecular compound.
IUPAC has set the following order for writing the elements in a binary molecular compound:
C, P, N, H, S, I, Br, Cl, O, and F
Notice they are arranged according to increasing electronegativity.
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Chapter 7

61. Naming Binary Molecular Compounds
The first element in the compound is named first and the second element has the suffix -ide.
The number of atoms of each element must be indicated by Greek prefixes.
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Chapter 7

62. Naming Binary Molecular Compounds, Continued
The molecular compound P4S3 is used on match tips. What is the name of P4S3?
There are 4 P atoms, use tetra-.
There are 3 S atoms, use tri-.
The name for P4S3 is tetraphosphorous trisulfide.
What is the name for N2O4?
Dinitrogen tetraoxide
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63. An Exception
There is one exception to the use of the Greek prefixes when naming binary molecular compounds.
If there is only one atom of the first element, the mono- is not used. The prefix mono- is always used for the second element.
CO is carbon monoxide.
XeF6 is xenon hexafluoride.
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64. Molecular Compounds HI hydrogen iodide NF3 nitrogen trifluoride SO2
sulfur dioxide
N2Cl4
dinitrogen tetrachloride
TOXIC!
NO2
nitrogen dioxide
N2O
dinitrogen monoxide
Laughing Gas

65. Let's Practice
Name the following covalent compounds
1. SiO2
2. N2O5
3. CCl4
4. IF7

66. Example Video Naming Molecular Compounds (5:22 min)
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Chapter 4

67. Binary Acids
A binary acid is an aqueous solution of a compound containing hydrogen and a nonmetal.
The formula of an acid always begins with H:
HF (aq)
Binary acids are named by using the prefix hydro- before the element stem and adding the suffix ic acid.
HF (aq) is hydrofluoric acid.
HI (aq) is hydroiodic acid.
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69. Ternary Oxyacids
Ternary oxyacids are aqueous solutions of a compound containing hydrogen and an oxyanion.
If the acid is derived from an oxyanion ending in -ate, the suffix is changed to -ic acid.
HNO3 (aq) is nitric acid (from NO3-, nitrate ion).
If the acid is derived from an oxyanion ending in -ite, the suffix is changed to -ous acid.
HNO2 (aq) is nitrous acid (from NO2-, nitrite ion).
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70. Acid anions (provide H+ ions)
Uses of mono– and di-
Rule: to be used if oxyanion is bonded to one or more hydrogen ions.
Example:
HPO42- = monohydrogen phosphate ion
H2PO4- = dihydrogen phosphate ion

73. Oxyanions and Oxyacids
Below is an example of ternary oxyacid and ternary compound naming.
Ternary Oxyacid
Ternary Compound
HClO hypochlorous acid
NaClO sodium hypochlorite
HClO2 chlorous acid
NaClO sodium chlorite
HClO3 chloric acid
NaClO sodium chlorate
HClO4 perchloric acid
NaClO sodium perchlorate
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Chapter 7

74. Example Video Naming Acids (10:28 min)
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Chapter 4

75. Let's Practice Nomenclature
Name the following compounds using the Stock System
1. NH4Cl
2. BaSO4
3. Fe(NO3)3
4. CuHCO3
5. Ca(OH)2

76. More Practice Na2SO4 Na2SO3 Sodium Sulfate Sodium Sulfite AgCN Cd(OH)2
Silver Cyanide Cadmium Hydroxide
Ca(OCl)2 KClO4
Calcium Hypochlorite Potassium Perchlorate

78. Chapter Summary Most inorganic compounds do not contain carbon.
Binary ionic compounds are composed of a metal and a nonmetal.
Ternary ionic compounds are composed of a metal, a nonmetal, and oxygen.
Binary molecular compounds are composed of two nonmetal elements.
Acids are composed of hydrogen and a nonmetal atom or an oxyanion.
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Chapter 7

79. Chapter Summary, Continued
Cations are named the element plus the word ion.
Cations with more than one possible charge have their charge indicated with Roman numerals in parentheses.
Ionic compounds are named using the cation first, anion second. Then anion has the suffix -ide added.
The simplest representative unit for an ionic compound is a formula unit.
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Chapter 7

80. Chapter Summary, Continued
The simplest representative unit for a molecular compound is a molecule.
When naming molecular compounds, the elements are written in the order C, P, N, H, S, I, Br, Cl, O, then F.
The name of the first element is the same; the suffix -ide is added to the second element.
Greek prefixes are used to indicate the number of each atom in the formula.
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81. Chapter Summary, Continued
An acid is an aqueous solution of a compound containing hydrogen and a nonmetal or an oxyanion.
Binary acids are named for the nonmetal atom by adding the prefix -hydro and the suffix -ic acid.
Ternary oxyacids are named by changing the -ate suffix on the oxyanion to -ic acid, or the -ite suffix on the oxyanion to -ous acid.
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Chapter 7