CHEM1-MIDTERM-W9-10-Chemical Nomenclature (Ionic and Covalent Compounds).ppt

Lessons

1. Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Naming Ionic and Covalent
Compounds
CHEMICAL
NOMENCLATURE

2. A compound is a substance composed of two or more elements
combined in a specific ratio and held together by chemical bonds.
Familiar examples of compounds are water and salt (sodium
chloride).
CompoundsCompounds

3. Ionic Compounds and BondingIonic Compounds and Bonding
The resulting electrically neutral compound, sodium chloride, is
represented with the chemical formula NaCl.
The chemical formula, or simply formula, of an ionic compound
denotes the constituent elements and the ratio in which they
combine.

4. A monatomic ion is named by changing the ending of the
element’s name to –ide.
Cl
–
is chlorideO
2–
is oxide
Some metals can form cations of more than one possible charge.
Fe
2+
: ferrous ion [Fe(II)]
Fe
3+
: ferric ion [Fe(III)]
Mn
2+
: manganese(II) ion
Mn
3+
: manganese(III) ion
Mn
4+
: manganese(IV) ion
Naming Ions and Ionic CompoundsNaming Ions and Ionic Compounds

5. Naming Ions and Ionic CompoundsNaming Ions and Ionic Compounds

6. Naming Ions and Ionic CompoundsNaming Ions and Ionic Compounds
Formulas for ionic compounds are generally empirical formulas.
Ionic compounds are electronically neutral.

7. Al
3+
O
2–
Al
2
O
3
In order for ionic compounds to be electronically neutral, the sum
of the charges on the cation and anion in each formula must be
zero.
Aluminum oxide:
Sum of charges:2(+3) + 3(–2) = 0
Formulas of Ionic CompoundsFormulas of Ionic Compounds

8. Formulas of Ionic CompoundsFormulas of Ionic Compounds

9. Naming Ions and Ionic CompoundsNaming Ions and Ionic Compounds
To name ionic compounds:
1) Name the cation
omit the word ion
use a Roman numeral if the cation can have more than one
charge
2) Name the anion
omit the word ion
Examples:
NaCN sodium cyanide
FeCl
2 iron(II) chloride
FeCl
3iron(III) chloride

10. Polyatomic ions consist of a combination of two or more atoms.
Formulas are determined following the same rule as for ionic
compounds containing only monatomic ions: ions must combine in
a ratio that give a neutral formula overall.
Calcium phosphate:
Covalent Bonding in Ionic SpeciesCovalent Bonding in Ionic Species
Ca
2+
PO
4
3–
Ca
3(PO
4)
2
Sum of charges:3(+2) + 2(–3) = 0

11. Covalent Bonding in Ionic SpeciesCovalent Bonding in Ionic Species

12. Covalent Bonding in Ionic SpeciesCovalent Bonding in Ionic Species

13. Worked Example
Strategy Begin by identifying the cation and anion in each compound, and then
combine the names for each, eliminating the word ion.
Name the following ionic compounds: (a) Fe
2
(SO
4
)
3
, (b) Al(OH)
3
, and (c) Hg
2
O.
Solution (a) Fe
2(SO
4)
3 is iron(III) sulfate.
(b) Al(OH)
3 is aluminum hydroxide.
(c) Hg
2O is mercury(I) oxide.
Think About It Be careful not to confuse the subscript in the formula with the
charge in the metal ion. In part (a), for example, the subscript on Fe is 2, but this
is an iron(III) compound.

14. Covalent Bonding in Ionic SpeciesCovalent Bonding in Ionic Species
Oxoanions are polyatomic anions that contain one or more oxygen
atoms and one atom (the “central atom”) of another element.
Starting with the oxoanions that end in –ate, we can name these
ions as follows:
1)The ion with one more O atom than the –ate ion is called the
per…ate ion. Thus, ClO
3
-
is the chlorate ion, so ClO
4
-
is the
perchlorate ion.
2)The ion with one less O atom than the –ate ion is called the –ite
ion. Thus, ClO
2
-
is the chlorite ion.
3)The ion with two fewer O atom than the –ate ion is called the
hypo…ite ion. Thus, ClO
-
is the hypochlorite ion.
At minimum, memorize the oxoanions that end in –ate so you can
apply these guidelines when necessary.

15. Covalent Bonding in Ionic SpeciesCovalent Bonding in Ionic Species
perchlorate ClO
4
-
chlorate ClO
3
-
chlorite ClO
2
-
hypochloriteClO
-
nitrate NO
3
-
nitrite NO
2
-
phosphate PO
4
3-
phosphite PO
3
3-
sulfate SO
4
2-
sulfite SO
3
2-

16. Worked Example 5.10
Strategy Each species is either an oxoanion or an oxoacid. Identify the
“reference oxidation” (the one with the –ate ending) for each, and apply the rules
to determine appropriate names.
Name the following species: (a) BrO
4
-
, (b) HCO
3
-
, and (c) H
2
CO
3
.
Solution (a) BrO
4
-
has one more O atom than the bromate ion (BrO
3
-
), so BrO
4
-

is the perbromate ion.
(b) CO
3
2-
is the carbonate ion. Because HCO
3
-
has one ionizable hydrogen atom,
it is called the hydrogen carbonate ion.
(c) With two ionizable hydrogen atoms and no charge on the compound, H
2CO
3
is carbonic acid.
Think About It Make sure that the charges sum to zero in each compound
formula. In part (a), for example, Hg
2+
+ 2Cl
-
= (+2) + 2(-1) = 0; in part (b),
(+2) + 2(-1) = 0; and in part (c), 3(+1) + (-3) = 0.
Think About It Remembering all these names and formulas is
greatly facilitated by memorizing the common ions that end in –ate.
chlorate ClO
3
-
nitrate
NO
3
-
iodate IO
3
-
carbonate CO
3
2-
bromate BrO
3
-
oxalate
C
2O
4
2-
sulfate SO
4
2-
chromate
CrO
4
2-
phosphate PO
4
3-
permanganate
MnO
4
-

17. Worked Example 5.11
Strategy The –ous ending in the name of an acid indicates that the acid is
derived from an oxoanion ending in –ite. The oxoanion must be sulfite, SO
3
2-
, so
add enough hydrogen ions to make a neutral formula.
Determine the formula of sulfurous acid.
Solution The formula of sulfurous acid is H
2SO
3.
Think About It Remembering all these names and formulas is greatly
facilitated by memorizing the common ions that end in -ate.

18. HydratesHydrates
A hydrate is a compound that has a specific number of water
molecules within its solid structure.
For example, in its normal state, copper(II) sulfate has five water
molecules associated with it.
Systematic name: copper(II) sulfate pentahydrate
Formula: Cu(SO)
4
∙ 5H
2
O
Some other hydrates are
BaCl
2 ∙ 2H
2O
LiCl ∙ H
2O
MgSO
4
∙ 7H
2
O
Sr(NO
3
)
2
∙ 4H
2
O

19. HydratesHydrates
When the water molecules are driven off by heating, the resulting
compound, Cu(SO)
4
, is sometimes called anhydrous copper(II)
sulfate.
Anhydrous means the compound no longer has water molecules
associated with it.

20. Familiar Inorganic CompoundsFamiliar Inorganic Compounds

21. Covalent Bonding and MoleculesCovalent Bonding and Molecules

22. A chemical formula denotes the
composition of the substance.
A molecular formula shows the exact
number of atoms of each element in a
molecule.
Some elements have two or more distinct
forms known as allotropes.
For example, oxygen (O
2
) and ozone
(O
3) are allotropes of oxygen.
A structural formula shows not only the
elemental composition, but also the
general arrangements.
Covalent Bonding and MoleculesCovalent Bonding and Molecules

23. Molecular substances can also be represented using empirical
formulas, the whole-number ratio of elements.
While, the molecular formulas tell us the actual number of atoms (the
true formula), the empirical formula gives the simplest formula.
Molecular formula: N
2
H
4
Empirical formula: NH
2
The molecular and empirical formulas are often the same.
Covalent Bonding and MoleculesCovalent Bonding and Molecules

24. Covalent Bonding and MoleculesCovalent Bonding and Molecules

25. Remember that binary molecular compounds are substances that
consist of just two different elements.
Nomenclature:
1) Name the first element that appears in the formula.
2) Name the second element that appears in the formula,
changing its ending to –ide.
Examples:
HCl hydrogen chloride
HI hydrogen iodide
Naming Molecular CompoundsNaming Molecular Compounds

26. Greek prefixes are used to denote the number of atoms of each
element present.
Naming Molecular CompoundsNaming Molecular Compounds

27. The prefix mono- is generally omitted for the first element.
For ease of pronunciation, we usually eliminate the last letter of a
prefix that ends in “o” or “a” when naming an oxide.
Example: N
2O
5 is dinitrogen pentoxide not dinitrogen
pentaoxide
Naming Molecular CompoundsNaming Molecular Compounds

28. Worked Example 5.7
Strategy Each compound will be named using the systematic nomenclature
including, where necessary, appropriate Greek prefixes.
Name the following binary molecular compounds: (a) NF
3
and (b) N
2O
4.
Solution (a) nitrogen trifluoride
(b) dinitrogen tetroxide
Think About It Make sure that the prefixes match the subscripts in the
molecular formulas and that the word oxide is not preceded immediately by an
“a” or an “o”.

29. Worked Example 5.8
Strategy The formula for each compound will be deduced using the systematic
nomenclature guidelines.
Write the chemical formulas for the following binary molecular compounds:
(a) sulfur tetrafluoride and (b) tetraphosphorus decasulfide.
Solution (a) SF
4
(b) P
4
S
10
Think About It Double-check that the subscripts in the formulas match the
prefixes in the compound names: (a) 4 = tetra and (b) 4 = tetra and 10 = deca.

30. The names of molecular compounds containing hydrogen do not
usually conform to the systematic nomenclature guidelines.
Many are called by the common, nonsystematic names or by names
that do not indicate explicitly the number of H atoms present.
Examples:
B
2
H
6
Diborane
SiH
4
Silane
NH
3 Ammonia
PH
3 Phosphine
H
2
O Water
H
2
S Hydrogen sulfide
Compounds Containing HydrogenCompounds Containing Hydrogen

31. Compounds Containing HydrogenCompounds Containing Hydrogen
One definition of an acid is a substance that produces hydrogen
ions (H
+
) when dissolved in water.
HCl is an example of a binary compound that is an acid when
dissolved in water.
To name these types of acids:
1) remove the –gen ending from hydrogen
2) change the –ide ending on the second element to –ic.
hydrogen chloride → hydrochloric acid

32. Compounds Containing HydrogenCompounds Containing Hydrogen
A compound must contain at least one ionizable hydrogen atom to
be an acid upon dissolving.

33. A molecule is an aggregate of two or more atoms in a
definite arrangement held together by chemical bonds
H
2 H
2O NH
3 CH
4
A diatomic molecule contains only two atoms
H
2, N
2, O
2, Br
2, HCl, CO
A polyatomic molecule contains more than two atoms
O
3
, H
2
O, NH
3
, CH
4

34. Writing Chemical Formals
One way to remember these
elements is:
Mr. BrINClHOF
There are 7 elements that occur in nature as a diatomic molecule

35. A monatomic ion contains only one atom
A polyatomic ion contains more than one atom
Na
+
, Cl
-
, Ca
2+
, O
2-
, Al
3+
, N
3-
OH
-
, CN
-
, NH
4
+
, NO
3
-

36. 2.5

37. Guidelines for Writing Chemical Formulas
for Binary Compounds
1.Except for Hydrogen, the element farther to the left in the
periodic table appears first. Ie: KCl, PCl
3
, Al
2
S
3
, and Fe
3
O
4
2.If hydrogen is present, it appears last except when the other
element is from group 16 or 17. Ie: LiH, NH
3
, B
2
H
6
, CH
4
H
2O, HCl and HI
3.If both elements are from the same group, the lower one
appears first. Ie: SiC and BrF
3

38. A molecular formula shows the exact number of
atoms of each element in the smallest unit of a
substance
An empirical formula shows the simplest
whole-number ratio of the atoms in a substance
H
2
OH
2O
molecular empirical
C
6H
12O
6
CH
2O
O
3
O
N
2H
4 NH
2

39. 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

40. Formula of Ionic Compounds
Al
2
O
3
2 x +3 = +6 3 x -2 = -6
Al
3+
O
2-
CaBr
2
1 x +2 = +2 2 x -1 = -2
Ca
2+
Br
-
Na
2
CO
3
1 x +2 = +2 1 x -2 = -2
Na
+
CO
3
2-

41. M
U
S
T
K
N
O
W
Ion Name (common name) Ion Name (Common name)
NH
4
+
Ammonium CO
3
2-
Carbonate
H
3
O
+
Hydronium HCO
3
-
Hydrogen carbonate (bicarbonate)
OH
-
Hydroxide SO
3
2-
Sulfite
CN
-
Cyanide HSO
3
-
Hydrogen sulfite
NO
2
-
Nitrite SO
4
2-
Sulfate
NO
3
-
Nitrate HSO
4
-
Hydrogen sulfate
ClO
-
Hypochlorite (often written
OCl
-
)
SCN
-
Thiocyanate
ClO
2
-
Chlorite S
2
O
3
2-
Thiosulfate
ClO
3
-
Chlorate CrO
4
2-
Chromate
ClO
4
-
Perchlorate Cr
2
O
7
2-
Dichromate
MnO
4
-
Permanganate PO
4
3-
Phosphate
CH
3
CO
2
-
Acetate (can be written
C
2H
3O
2
-
)
HPO
4
2-
Hydrogen phosphate
C
2
O
4
2-
Oxalate H
2
PO
4
-
Dihydrogen phospate

42. Recognizing Ionic Compounds
A compound is ionic if it contains a metal from group 1
Or group 2 or one of the polyatomic ions. Binary metal
Oxides and sulfides also have ionic character
Fig 2-23
Pg 59
Pure water(left)
and a solution
of sugar(right)
do not conduct
electricity
because they
contain virtually
no ions. A
solution of salt
(center)
conducts
electricity well
because it
contain mobile
cationsand
anions.Courtesy Ken Karp

43. Chemical Nomenclature
•Ionic Compounds
–often a metal + nonmetal
–anion (nonmetal), add “ide” to element name
BaCl
2
barium chloride
K
2
O potassium oxide
Mg(OH)
2
magnesium hydroxide
KNO
3
potassium nitrate

44. Cations of Variable Charge
Transition metals such as copper may form cations
Of different charge. This is represented by placing a
Roman numeral after the transition metal in
Parentheses after the name of the metal.
CuO Copper(II) oxide
Cu
2
O Copper(I) oxide

45. •Transition metal ionic compounds
–indicate charge on metal with Roman numerals
FeCl
22 Cl
-
-2 so Fe is +2iron(II) chloride
FeCl
33 Cl
-
-3 so Fe is +3iron(III) chloride
Cr
2
S
33 S
-2
-6 so Cr is +3 (6/2)chromium(III) sulfide

46. •Molecular compounds
•nonmetals or nonmetals + metalloids
•common names
•H
2O, NH
3, CH
4, C
60
•element further left in periodic table
is 1
st
•element closest to bottom of group is
1
st
•if more than one compound can be
formed from the same elements, use
prefixes to indicate number of each
kind of atom
•last element ends in ide

47. HI hydrogen iodide
NF
3
nitrogen trifluoride
SO
2
sulfur dioxide
N
2
Cl
4
dinitrogen tetrachloride
NO
2 nitrogen dioxide
N
2
O dinitrogen monoxide
Molecular Compounds
TOXIC!
Laughing Gas

48. 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.
HNO
3
nitric acid
H
2CO
3
carbonic acid
H
2SO
4 sulfuric acid
HNO
3

49. A base can be defined as a substance that yields
hydroxide ions (OH
-
) when dissolved in water.
NaOH sodium hydroxide
KOH potassium hydroxide
Ba(OH)
2
barium hydroxide

50. Hydrates
A hydrate is an ionic compound that has water molecules
Incorporated into their solid structures
Writing the formula: name of ionic compound-# H
2
O
Pg 89
The Hydrate of copper
sulfate is the pentahydrate,
and the anhydrous copper
sulfate will absorb water
to form the Hydrate.
CuSO
45 H
2O.
Copper(II)sulfate
.
pentahydrate
Olmsted Williams

51. Writing Chemical Formulas
For non ionic compounds with more than 2 atoms
Write Carbon first
Hydrogen second
All other elements in alphabetical order
4 Hydrogen
2 Carbons
4 oxygens
1 Fluorine
1 Sulfur
C
2H
4FlO
4S
4 Carbons
1 Bromine
8 Hydrogen
1 Chlorine
2 Nitrogen
4 Oxygens
C
4
H
8
BrClN
2
O
4

Let’s try some………………
4 Iodines
6 Carbons
10 Hydrogens
C
6
H
10
I
4

52. Practice:

53. Practice: