Chapter 4
Ionic Compounds
Chemical Bonds
• 2-types of bonding are found in
compounds
– Ionic bond – Chapter 4
– Covalent bond – Chapter 5
Ions
• Ionic compounds – substances comprised
of ions of a metal combined with ions of a
nonmetal or group of non-metals
Ions
• Metals
– Lose electrons
– Forms a cation
• Nonmetals
– Gain electrons
– Forms an anion
Ions and the Octet Rule
• Stated
– Metals form cations
– Nonmetals form anions
• Why?
– An ion is formed so that the atom achieves noble gas
configuration
• Octet Rule – main group elements tend to undergo reactions
that leave them with 8 electrons in outer shell
– Outer shell – valence shell – highest period #
– Outer electrons – valence electrons – e- in highest period #
Electron-Dot Symbols
• Electron-dot symbol – An atomic symbol with
dots placed around it to indicate the number of
valence electrons
Periodic Properties and Ion
Formation
• Ease by which an element forms a cation
or anion is determined by the energy
involved
Periodic Properties and Ion
Formation
• Ease by which a cation is formed – ionization
energy
– Metals have lower ionization energies than nonmetals
– Ionization energy increases across a period
– Ionization energy decreases down a group
Periodic Properties and Ion
Formation
• Ease by which an anion is formed –
electron affinity
– Nonmetals have larger electron affinities
– Electron affinity values become more negative
across a group
– Electron affinity values become less negative
down a group
Ionic Bond
• Ionic bond – the glue that holds the metal and
nonmetal together
– Electrostatic attraction (magnets) – occurs when
opposites attract
Some Properties of Ionic
Compounds
• Usually crystalline
• Ions in a solid do not move – do not conduct
electricity
• Once dissolved – ions move freely and conduct
electricity
• High melting and boiling points
• Ionic solids shatter if struck hard
• Ionic compounds dissolve in water if the
attraction of ions to water is greater than the ions
attraction to each other
Ionic Bonds
Problem
• Which of the following ions occurs
commonly?
– A.
– B.
– C.
– D.
– E.
N3+
S6+
O2Ca+
Cl+
Problems
• Which of the following ions occurs
commonly?
– A.
– B.
– C.
– D.
– E.
P3+
Br7+
O6+
Ca2+
K-
Ionic Bonds
Naming Ions
• Group 1A, Group 2A, Al, Ga, In, Zn, Sc, Ag, Cd,
Ru ions
– Give name of element followed by word ion
• All other metals
– Give name of element + charge in parenthesis (roman
numerals) followed by word ion
• Element anions
– Replace the ending of the element name with -ide
Polyatomic Ions
• Polyatomic ion
– Poly – many
– Atomic – atom
– Ion – ion
• Think of them as a chemical unit
– States which atoms are present, exact #
atoms present and the charge
Polyatomic Ions
Problem
• Which one of the following combinations of
names and formulas of ions is incorrect?
– A.
– B.
– C.
– D.
– E.
O2- oxide
Al3+ aluminum
NO3- nitrate
PO43- phosphate
CrO42- chromate
Problem
• Which one of the following combinations of
names and formulas of ions is incorrect?
– A.
– B.
– C.
– D.
– E.
O2- oxide
Cd2+ cadmium
ClO3- chlorate
HCO3- hydrogen carbonate
NO2- nitrate
Problem
• Which one of the following combinations of
names and formulas of ions is incorrect?
– A.
– B.
– C.
– D.
– E.
Ba2+ barium
S2- sulfate
CN- cyanide
ClO4- perchlorate
HCO3- bicarbonate
Naming Ionic Compounds
• Simply combine the names previously discussed
in naming ions without the word ion
• Determine which element is the cation
– Can the cation only have one possible charge
• Yes
– Give the name of the metal as seen on periodic table
– Give the anion the root name of the element followed
by the ending –ide
• Polyatomic ions – get their name
Naming Ionic Compounds
• No
– Give the name of the metal as seen on
periodic table
– Indicate the charge on the metal
• Use roman numerals in parenthesis
– Give the anion the root name of the element
followed by the ending –ide
• Polyatomic ions – get their name
Problem
• The colorless substance, MgF2, is used in the
ceramics and glass industry. What is its name?
–
–
–
–
–
A. magnesium difluoride
B. magnesium fluoride
C. magnesium(II) fluoride
D. monomagnesium difluoride
E. none of these choices is correct, since they are all
misspelled
Problem
• The compound, BaO, absorbs water and carbon
dioxide readily and is used to dry gases and
organic solvents. What is its name?
–
–
–
–
–
A.
B.
C.
D.
E.
barium oxide
barium(II) oxide
barium monoxide
baric oxide
barium peroxide
Problem
• The substance, CoCl2, is useful as a humidity
indicator because it changes from pale blue to
pink as it gains water from moist air. What is its
name?
–
–
–
–
–
A.
B.
C.
D.
E.
cobalt dichloride
cobalt(II) chloride
cobalt chloride
cobaltic chloride
copper(II) chloride
Problem
• A red glaze on porcelain can be produced
by using MnSO4. What is its name?
– A.
– B.
– C.
– D.
– E.
manganese disulfate
manganese(II) sulfate
manganese(IV) sulfate
manganese sulfate
manganese(I) sulfate
Problem
• The substance, KClO3, is a strong oxidizer
used in explosives, fireworks, and
matches. What is its name?
– A.
– B.
– C.
– D.
– E.
potassium chlorite
potassium chloride
potassium(I) chlorite
potassium(I) chlorate
potassium chlorate
Problem
• The compound, (NH4)2S, can be used in
analysis for trace amounts of metals
present in a sample. What is its name?
– A.
– B.
– C.
– D.
– E.
ammonium sulfide
diammonium sulfide
ammonium sulfite
ammonia(I) sulfite
ammonium(I) sulfide
Problem
• The substance, CaSe, is used in materials
which are electron emitters. What is its
name?
– A.
– B.
– C.
– D.
– E.
calcium monoselenide
calcium(II) selenide
calcium selenide
calcium(I) selenide
calcium(II) selenium
Formulas of Ionic Compounds
• Chemical compounds must posses NO charge
• Formulas
– Determine ions involved
– Determine charge on each ion
– Cross and drop the magnitude
• If the magnitude dropped beside a polyatomic is greater than
1, place the polyatomic ion in parenthesis and magnitude
dropped as subscript outside parenthesis
– Simplify if the subscripts are divisible by same #
Problem
• Sodium oxide combines violently with
water. Which of the following gives the
formula for sodium oxide?
– A.
– B.
– C.
– D.
– E.
NaO
Na1O1
Na2O1
Na2O
Na2O2
Problem
• Barium fluoride is used in embalming and in
glass manufacturing. Which of the following
gives the formula for barium fluoride?
–
–
–
–
–
A.
B.
C.
D.
E.
BaF2
Ba1F2
BaF
BaF1
Ba2F
Problem
• Zinc acetate is used in preserving wood
and in manufacturing glazes for porcelain.
What is its formula?
– A.
– B.
– C.
– D.
– E.
ZnAc2
ZnCH3COO
Zn(CH3COO)2
Zn2CH3COO
ZnCH3COCH3
Problem
• Barium sulfate is used in manufacturing
photographic paper. What is its formula?
– A.
– B.
– C.
– D.
– E.
BaSO4
Ba(SO4)2
Ba2SO4
Ba2(SO4)3
BaSO3
Problem
• What is the formula for lead (II) oxide?
– A.
– B.
– C.
– D.
– E.
PbO
PbO2
Pb2O
PbO4
Pb2O3
H+ and OH- Ions: An Introduction to
Acids and Bases
• The importance of the H+ cation and the
OH- anion is that they are fundamental to
the concepts of acids and bases.
• Acid: A substance that provides H+ ions in
water; for example, HCl  H+ + Cl• Base: A substance that provides OH- ions
in water; for example, NaOH  Na+ +
OH-
Optional Homework
• Text – 4.31, 4.32, 4.33, 4.38, 4.46, 4.48,
4.50, 4.52, 4.54, 4.56, 4.60, 4.62, 4.64,
4.66, 4.68, 4.70, 4.72, 4.74, 4.76, 4.90,
4.92, 4.96, 4.98
• Chapter 2 Homework – from website
Required Homework
• Assignment 4