1. CHEM 1305 Introductory Chemistry
“Introductory Chemistry: Concepts and Critical Thinking – 7th Edition,
Charles H. Corwin
Chapter 6. Language of Chemistry
Modified by: Dr. Violeta F. Coarfa

2. Language of Chemistry – IUPAC Rules
The International Union of Pure and Applied Chemistry, IUPAC, has set rules for naming chemical compounds.
These rules, referred to as IUPAC nomenclature, are still in use today.
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3. Classification of Compounds
Below is a flow chart for the classification of inorganic compounds.
Most inorganic compounds do not contain the element carbon.
The exceptions are carbon dioxide, CO2, and carbonates, which contain the ion CO32–.
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4. Ionic Compounds Molecular 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.
Molecular Compounds
Binary molecular compounds contain two elements and both are nonmetals.
Some examples of binary molecular compounds are ammonia, NH3 and water, H2O.
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5. Aqueous Acids
A binary acid is an aqueous solution of a compound containing hydrogen and one other nonmetal.
HCl (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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6. Learning Check
Classify each of the following as a binary ionic compound, ternary ionic compound, binary molecular compound,
binary acid, or ternary oxyacid:
a. calcium oxide, CaO b. sulfur dioxide, SO2
c. silver chromate, Ag2CrO4 d. hydrofluoric acid, HF(aq)
e. carbonic acid, H2CO3(aq)
Solution:
We can refer to the periodic table and classify each compound or solution as follows:
a.CaO contains two elements, a metal and nonmetal. Thus, CaO is a binary ionic compound.
b.SO2 contains two elements, both nonmetals. Thus, SO2 is a binary molecular compound.
c.Ag2CrO4 contains three elements, two metals and a nonmetal. Thus, Ag2CrO4 is a ternary ionic compound.
d.HF(aq) is a compound of hydrogen and a nonmetal dissolved in water. Thus, HF(aq) is a binary acid.
e.H2CO3(aq) is a compound containing three elements, including hydrogen and oxygen, dissolved in water. Thus, H2CO3(aq) is a ternary oxyacid.
Practice Exercise
a. carbon disulfide, CS2 b. lithium dichromate, Li2Cr2O7
c. magnesium iodide, MgI2 d. nitric acid, HNO3(aq)
e. hydrochloric acid, HCl(aq)
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7. Valence electrons – Review Chapter 5
Niels Bohr speculated that electrons orbit about the nucleus in fixed energy levels.
Electrons are found only in specific energy levels, and nowhere else.
The electron energy levels are quantized.
Chapter 4
Valence Electrons: the electrons found in the outermost electron shell of an atom
Importance: they are important in determining how an element interacts chemically with
other elements, by following the octet rule
Number of valence electrons: given by the group number of the elements *
Octet Rule: Atoms lose, gain or share electrons in order to achieve the electronic configuration of the closest noble gas. **
* the count of valence electrons are not useful
** except for He, which has 2 electrons of valence

8. Electron-Dot Symbols (Lewis) - Review Chapter 5
Definition: convenient representations of the valence electrons
ns1 ns ns2np ns2np ns2np6
ns2np ns2np ns2np5
s-block and
p-block
Be careful - for Gr3A-7A (nonmetals): you must first draw a valence electron on
each side of the element, then the dots are paired

9. Ions and Ionic Charges – Review Chapter 5
Atoms lose or gain electron(s) and form positive or negative ions, which have an electronic configuration that looks like the closest noble gas configuration.
cation – ion with a positive charge
If a neutral atom of a metal loses one or more electrons it becomes a cation. Na
11 protons
11 electrons
Na+
11 protons
10 electrons -
- 1 e
metal
Na+ looks like the closest noble gas, Ne
anion – ion with a negative charge
If a neutral atom of a nonmetal gain sone or more electrons it becomes an anion.
Cl-
17 protons
18 electrons Cl
17 protons
17 electrons -
+ 1 e
nonmetal
Cl- looks like the closest noble gas, Ar
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10. Classification of Ions
From metal
From nonmetal
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11. Learning Check
Classify each of the following ions as a monoatomic cation, monoatomic anion, polyatomic cation, or polyatomic anion:
a. barium ion, Ba2+ b. chloride ion, Cl–
c. ammonium ion, NH4+ d. carbonate ion, CO32–
Solution:
We can classify each ion as follows:
a. Ba2+ is a single atom with a positive charge. Thus, Ba2+ is a monoatomic cation.
b. Cl– is a single atom with a negative charge. Thus, Cl– is a monoatomic anion.
c. NH4+ has five atoms and a positive charge. Thus, NH4+ is a polyatomic cation.
d. carbonate ion, CO32– has four atoms and a negative charge. Thus, carbonate ion, CO32– is a polyatomic anion.
Practice Exercise
a. hydronium ion, H3O+ b. sulfide ion, S2–
c. permanganate ion, MnO4– d. stannous ion, Sn2+
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12. Monoatomic Ions - Ionic Charges – Review Chapter 5
Main group
Valence Electrons
Lost electrons
Ionic Charge(s)
1 A 1 +1
2 A 2 +2
3 A 3
+3 (main charge);
+1 (secondary charge)
4 A 4
+4 (main charge);
+2 (secondary charge)
5 A 5
+5 (main charge);
+3 (secondary charge)
METALS lose e-
to become positive ions (cations)
Note: For transition metals - use Periodic Table
Main group
Valence Electrons
Gained electrons
Ionic Charge
4 A 4
8 - 4 e- = 4 e- -4
5 A 5
8 - 5 e- = 3 e- -3
6 A 6
8 - 6 e- = 2 e- -2
7 A 7
8 - 7 e- = 1 e- -1
NONMETALS gain e-
to become negative ions (anions)
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13. Common monatomic ions Pl Note: Please notice H with +1 and -1
Ga1+
Ga3+
In1+
In3+
Tl1+
Tl3+
Bi3+
Bi5+ Pl
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14. Monoatomic Positive Ions - Nomenclature
Cations are named for the parent atom followed by the word “ion.”
Na+ -- sodium ion;
Mg2+ -- magnesium 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+.
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.
Cu+ is the copper(I) ion.
Cu2+ is the copper(II) ion.
This is called the Stock system of naming transition metal cations.
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15. Latin (or Suffix) System
For metal ions with two common ionic charges
This system takes the Latin name of the element and adds the suffix –ous or –ic.
The cation with the lower charge receives the –ous suffix
The cation with the higher charge receives the –ic suffix.
The Latin system is less common than the Stock system.
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16. Monoatomic Negative Ions - Nomenclature
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.
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17. Learning Check
Provide the formula for the following monoatomic cations:
a. magnesium ion b. cobalt(II) ion c. fluoride ion d. oxide ion
Solution:
We can use the periodic table to predict the charge on a cation.
a. Mg2+. c. F–.
b. Co d. O2–
Practice Exercise
Supply a systematic name for the following monoatomic cations:
a. Al3+ b. Co3+ c. Br– d. N3–
Aluminium ion
Cobalt (III) ion
Bromide ion
Nitride ion
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18. Polyatomic Ion Names – NOMENCLATURE to be memorized!
phosphite, PO33-
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19. Learning Check
Provide a systematic name for each of the following polyatomic oxyanions:
a. CO32– b. CrO42–
c. ClO2– d. HSO4–
Solution:
We can make reasonable predictions for the names of many polyatomic ions. This makes the task of memorization much easier.
a. CO32– contains carbon, and we predict the name has the suffix –ate. Thus, we predict CO32– is named the carbonate ion.
b. CrO42– contains chromium, and we predict the name has the suffix –ate. Thus, we predict CrO42– is named the chromate ion.
c. ClO2– is related to ClO3–, which is named the chlorate ion. Because ClO2– has one less oxygen atom, the suffix changes to –ite. Thus, we predict ClO2– is named the chlorite ion.
d. HSO4– is related to the sulfate ion, SO42–. With the addition of hydrogen, the name becomes the hydrogen sulfate ion.
Practice Exercise
Provide the formula for each of the following polyatomic oxyanions:
a. acetate ion b. dichromate ion c. perchlorate ion d. hydrogen carbonate ion
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20. 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-
Crossover Rule
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21. Learning Check
Write the chemical formula for the following binary compounds given their constituent ions:
a. copper(I) oxide, Cu+ and O2– b. cadmium oxide, Cd2+ and O2–
c. cobalt(III) oxide, Co3+ and O2–
Solution:
a. The copper(I) ion has a charge of 1+, and the oxide ion has a charge of 2–. Thus, two positive ions are required for each negative ion in a neutral formula unit. The formula of copper(I) oxide is written Cu2O.
b. Because the cadmium ion and oxide ion each have a charge of 2, the ratio is 1:1, that is, Cd1O1. It is not necessary to write the subscript 1, and so the formula of cadmium oxide is simply CdO.
c. This example is more difficult. The cobalt(III) ion has a charge of 3+ and the oxide ion has a charge of 2–. Because the lowest common multiple is 6, two 3+ ions are required to cancel the charge of three 2– ions. The ratio is 2:3, and the formula of cobalt(III) oxide is written Co2O3.
Practice Exercise
a. iron(II) sulfide, Fe2+ and S2–
b. nickel (II) fluoride, Ni2+ and F–
c. lead(IV) oxide, Pb4+ and O2–
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22. Learning Check
Write the chemical formula for each of the following ternary compounds given their constituent ions:
a. calcium carbonate, Ca2+ and CO32– b. calcium hydroxide, Ca2+ and OH–
c. calcium phosphate, Ca2+ and PO43–
Solution:
a. Because the positive and negative ions each have a charge of 2, one positive ion and one negative ion are required to produce a neutral formula unit, and the formula is CaCO3. Calcium carbonate occurs naturally as ordinary chalk.
b. The positive ion has a charge of 2+, and the negative ion has a charge of 1–. Therefore, one positive ion and two negative ions are required to produce a neutral formula unit. Because OH– is a polyatomic ion, parentheses are required, and the formula is written Ca(OH)2. Calcium hydroxide is known as “slaked lime” and is sometimes used to mark the boundaries of an athletic field.
c. The positive ion has a charge of 2+, and the negative ion has a charge of 3–. The lowest common multiple of the charges is 6. Three positive ions are required for every two negative ions to produce a neutral formula unit. A calcium phosphate formula unit is written Ca3(PO4)2. Calcium phosphate is found in tooth enamel.
Practice Exercise
a. copper(II) permanganate, Cu2+ and MnO4–
b. iron(III) carbonate, Fe3+ and CO32– c. potassium dichromate, K+ and Cr2O72–
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23. Determining Ionic Charge in a Compound
Learning Check
Determine the ionic charge for iron in the mineral hematite, Fe2O3.
Solution:
The charge on an oxide ion is 2–, and there are three oxide ions.
The total negative charge must be equal to six negative: O2– + O2– + O2– = 6 negative
Because all compounds are electrically neutral, the total positive charge must equal the total negative charge: 6 negative = 6 positive. Thus, the two iron ions have a total charge of six positive: Fex+ + Fex+ = 6 positive Fex+ = 3 positive
The iron ion is therefore Fe3+. The name of Fe2O3 is iron(III) oxide according to the Stock system. It is named ferric oxide according to the Latin system.
Practice Exercise
Determine the ionic charge for each transition metal in the following compounds:
a. Cu3P
b. CoN
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24. Ionic Compounds - NOMENCLATURE
Rule: cation name + anion name
NaCl sodium chloride
MgI2 magnesium iodide
NH4Cl ammonium chloride
CaCO3 calcium carbonate
NaHCO3 sodium bicarbonate (sodium hydrogen carbonate)
FeCl2 iron (II) chloride OR ferrous chloride
FeCl3 iron (III) chloride OR ferric chloride
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25. Learning Check
Supply a systematic name for each of the following binary ionic compounds:
a. ZnO
b. SnF2
Solution:
We can name an ionic compound by designating the two ions.
a. ZnO contains the zinc ion and the oxide ion; ZnO is named zinc oxide.
b. SnF2 contains the tin(II) ion and the fluoride ion. Thus, SnF2 is named tin(II) fluoride. The Latin system name is stannous fluoride, which is an active ingredient in a popular toothpaste.
Practice Exercise
a. Mn3P2
b. Fe2S3
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26. Binary Molecular Compounds
Binary molecular compounds are composed of two nonmetal elements.
A molecule is the simplest representative particle of a binary molecular compound.
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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27. Naming Binary Molecular Compounds
What is the name of the molecular compound P4S3?
There are 4 P atoms, use tetra–.
There are 3 S atoms, use tri–.
The name for P4S3 is tetraphosphorus trisulfide.
What is the name for P4S7?
Tetraphosphorus heptasulfide
Note:
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 --- carbon monoxide.
XeF6 --- xenon hexafluoride.
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28. Molecular Compounds - Acids- NOMENCLATURE
A. Binary Acids HX(aq)       X = F, Cl, Br, or I : hydro+ ROOT+ “-ic” acid
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) - hydrofluoric acid
HCl(aq) - hydrochloric acid
HBr(aq) - hydrobromic acid
HI(aq) - hydroiodic acid
H2S(aq) - hydrosulfuric acid
B. Ternary Oxyacids HaXbOc
If one H+ ion is added to nitrate, NO3-  nitric acid, HNO3, is formed.
If one H+ ion is added to nitrite, NO2-  nitrous acid, HNO2, is formed
If two H+ ions are added to sulfate, SO42- sulfuric acid, H2SO4, is formed.
If two H+ ions are added to sulfite, SO32- sulfurous acid, H2SO3, is formed
If three H+ ions are added to phosphate, PO43-, phosphoric acid, H3PO4, is formed.
If three H+ ions are added to phosphite, PO33-, phosphorous acid, H3PO3, is formed.
Roots: H hydr-
C carb-
N nitr-
P phosph-
O ox-
S sulf-
Se selen-
F fluor-
Cl chlor-
Br brom-
I iod-
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29. Dr. Coarfa - Chem1305

30. Review Chapter 6
- Classification of Compounds: Ionic Compounds; Molecular Compounds, Aqueous Acids
Ions: Cations vs. Anions. Classification of ions: Monoatomic vs. Polyatomic
Formula of Ionic Compounds – Crossover Rule
Nomenclature: positive ions, negative ions, ionic compounds, molecular compounds, aq. acids .
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