Chapter 5
Types of Compounds
•Ionic Compounds
•Covalent
Compounds
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Electronegativity
(EN)
Def: The strength with
which an atom in a
bond pulls on e-s.
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Covalent Bonds
(bonds btwn 2 nonmetals)
Nonmetals have high electronegativity
values
(REVIEW)
Electrons are shared
single bond shares 1 pair electrons
double bond shares 2 pairs electrons
triple bond shares 3 pairs electrons
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Covalent Bonds
Two nonmetal atoms form a covalent bond
because they have less energy (are more stable!)
after they bonded
H +
H : H = HH = H2
H
hydrogen molecule
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Learning Check
Indicate whether a bond between
the following would be 1) Ionic 2)
covalent
____
A.
sodium & oxygen
____
B.
nitrogen & oxygen
____
C.
phosphorus & chlorine
____ D.
calcium & sulfur
____ E.
chlorine & bromine
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Solution
Indicate whether a bond between the
following would be 1) Ionic
2)
covalent
1 A.
sodium and oxygen
2 B.
nitrogen and oxygen
2 C.
phosphorus and chlorine
1 D.
calcium and sulfur
2 E.
chlorine and bromine
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Types of Covalent (Molecular) Cpds
1. Elements that form diatomic
molecules
2. Binary covalent compounds
3. Organic compounds/
Hydrocarbon
4. Acids & Bases
• (Common v. Formal Names)
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Diatomic Elements
Elements that exist as diatomic molecules
are : H2, F2, N2, O2, Cl2, Br2, I2
octets


N


+

N




N:::N
triple bond
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Learning Check
Use the name of the element to name a
diatomic molecules.
H2
hydrogen
N2
nitrogen
Cl2
_______________
O2
_______________
I2
_______________
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Solution
Use the name of the element to name the
following diatomic molecules.
H2
hydrogen
N2
nitrogen
Cl2
chlorine
O2
oxygen
I2
iodine
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Naming Binary Covalent Compounds
Two nonmetals (def of binary covalent)
 Name each element
 End the last element in -ide
 Add prefixes to show how many atoms of each
 (except when there’s only 1 atom of the 1st element listed)
Prefixes-(see Table 5.5, p 168 of text)
mon
1
penta
di
2
hexa
tri
3
hepta
tetra
4
octa
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6
7
8
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Learning Check
Fill in the blanks to complete the following
names of covalent compounds.
CO
carbon ______oxide
CO2
carbon _______________
PCl3
phosphorus _______chloride
CCl4
carbon ________chloride
N2O
_____nitrogen _____oxide
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Solution
CO
carbon monoxide
CO2
carbon dioxide
PCl3
phosphorus trichloride
CCl4
carbon tetrachloride
N2O
dinitrogen monoxide
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Learning Check
A.
P2O5
1) phosphorus oxide
2) phosphorus pentoxide
3) diphosphorus pentoxide
B.
Cl2O7
1) dichlorine heptoxide
2) dichlorine oxide
3) chlorine heptoxide
C.
Cl2
1) chlorine
2) dichlorine
3) dichloride
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Solution
A.
P2O5
3) diphosphorus pentoxide
B.
Cl2O7
1) dichlorine heptoxide
C.
Cl2
1) chlorine
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Naming Organic Compounds
• Def: organic compounds
contain __ atoms hooked
together.
• (Why do you think this element
can hook up with many other
atoms, including itself?)
Hydrocarbons-A Type of Organic
Compound
• Def: hydrocarbons are
made of ___ & ___
• They are named by the
number of Carbon atoms
a molecule contains.
• See Table 5.8, p 183
Table 5.8: Hydrocarbons
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C8H18
C9H20
C10H22
methane
ethane
propane
butane
pentane
hexane
heptane
octane
nonane
decane
Common v. Formal Names
• Formal Names follow the
rules we have learned for
naming compounds.
• Common Names are ones
that don’t follow these rules.
–Ex: water=
Frequently Used Common
Names
• Water = H2O
• Ammonia = NH3
• Common Acids & Bases
Acids & Bases
(Table 5.7, p 182)
ACIDS
Formula
Name
HCl
H2SO4
H3PO4
HNO3
HC2H3O2
hydrochloric acid
sulfuric acid
phosphoric acid
nitric acid
acetic acid (vinegar)
Table 5.7 (cont.):
BASES
Formula
Name
NaOH
sodium hydroxide
KOH
potassium hydroxide
NH3
ammonia
Covalent Bonds in NH3
Bonding pairs
H

H
:
N
:
H

Lone pair of electrons
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Allotropes
• Def: molecules of the same element
that differ in structure
• Ex: Carbon…graphite, charcoal,
Buckminsterfullerine (“bucky
ball”)
- see Fig ___ on p ___ of text
• Ex2: O2 (oxygen) and O3 (ozone)
Q:Why do we have to specify the
number of atoms of each element in
a covalent compound?
A: Atoms of the same elements
can combine in different ratios.
• Ex: C & O
CO
CO2
Writing Formulas for Covalent
Compounds
1. Identify it as a covalent: containing only
nonmetals.
2. Determine what type of covalent it is:
diatomic element
binary
hydrocarbon (ends in –ane)
acid/base
3. Reverse the naming process.
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Naming Ionic Compounds
• Binary Ionic
• Ionic Compounds containing Polyatomic Ions.
• Ionic Cpds containing
Transition Metals
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PLEASE NOTE:
• IF YOU ARE UNABLE TO
IDENTIFY IONIC &
COVALENT COMPOUNDS,
YOU WILL BE LOST!!!
• PLEASE SEE ME
IMMEDIATELY TO GET
CAUGHT UP.
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Ionic Bonding & Electronegativity
Nonmetals have high EN’s.
 Metals have low EN’s.
Bonds between a metal & a nonmetal
involve transfers of e-s b/c of the big
difference in EN!
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Binary Ionic
Compounds
•Binary= 2 elements
•Ionic= 1 metal & 1
nonmetal
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Naming Binary Ionic Compounds
1. Identify & name the 2
elements in the compound.
2. Name the cation, which is the
given the name of the element.
3. Name the anion, which is
given the name of the element,
w/the ending changed to “–ide.”
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PRACTICE Naming Binary
Ionic Compounds
1. Na║Cl
2. Na = “sodium”
3. Cl = “chloride”
(full name is “sodium chloride”)
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PRACTICE Naming Binary
Ionic Compounds
1. Li2O
2 & 3.
____║____= ______ ______
(cation
(anion (cation name) (anion name)
symbol) symbol)
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MORE PRACTICE Naming Binary
Ionic Compounds-p __ of I.N.
1. KF
2. CaF2
3. Al2O3
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Naming Ionic Compounds
w/ Polyatomic Ions
• DEF: Charged particles
containing more than 1 type
2of atom. Ex: SO4
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Naming Ionic Compounds w/
Polyatomic Ions
1. Identify the cation & the
anion. (Draw a line
between the 2 ions)
2. Name the cation, then the
anion (find polyatomics on
Table 5.3, p 159 of text).
That’s it!
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PRACTICE :Naming Ionic
Compounds w/ Polyatomic Ions
EX: Na2SO4
____║____= ______
______
(cation
(anion (cation name) (anion name)
symbol) symbol)
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Naming Ionic Compounds w/
Polyatomic Ions
• Most polyatomic ions are
anions.
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A Couple of Important
Exceptions w/Polyatomic Ions
Important Exception #1: there are 2 cations that
contain NO METALS:
NH4+ (ammonium)
H3O+ (hydronium)
(this can be tricky b/c we have always identified
ionic compounds because they start with a
metal cation.)
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A Couple of Important
Exceptions w/Polyatomic Ions
Important Exception #2: Some anions contain
metals.
Ex: MnO4- = permanganate
Cr2O72- = dichromate
(this can be tricky b/c anions are usually a
nonmetal)
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Copy Table 5.2 into Notes
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Naming Ionic Cpds Containing
Ex: NiO2 Transition Metals
1. Determine the total # of negative charges
in a unit of the compound:
Ex: O2- & O2= 4 total - charges
2. Determine the charge on the cation that will
give you 4 total + charges Ex: Ni4+
3. Write the cation & anion names. Write
cation with the oxidation # written as a
Roman numeral in parentheses:
Ex: nickel (IV) oxide
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Writing Formulas for Binary
Ionic Compounds
1. Identify the ionic
charge (“oxidation
number”) on the
cation & anion.
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Writing Formulas for Binary
Ionic Compounds
ELEMENT
• Group 1
• Group 2
• Group 13
• Group 14
• Group 15
• Group 16
• Group 17
OXIDATION #
1+
2+
3+
4+ or 4321-Timberlake
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Practice Predicting Oxidation #s
•
•
•
•
•
Li
O
Mg
F
B
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Writing Formulas for Binary
Ionic Compounds
2. A compound has NO
CHARGE on it, so a formula
unit (the smallest ratio of
cations to anions) must have
equal numbers of + & charges. (use the LCM)
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Cross-Over Method
• You can use this to write formulas.
• Take the charge on the cation and
use it as the subscript on the anion
• Take the charge on the anion and
use it as the subscript on the cation
• Reduce the subscripts, if necessary
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Using the LCM to Write Ionic
Formulas
• Ex: Li & F
• Ex: Li & O
• Ex: Al & O
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ANSWERS
• LiF
• Li2O
• Al2O3
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Writing Formulas for I.Cpds
Containing Polyatomic Ions
• Determine the cation & anion
• Determine the oxidation # on
each ion. (oxidation #s for
polyatomics are found on Table 5.2)
• Write a balanced formula
–If there is more than 1 of an ion,
use parentheses, then a subscript
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Writing Formulas for I.Cpds
Containing Polyatomic Ions
• Ex: see Practice Problems, p 162
3. Write the formula for the compound formed
from the following pairs of ions
a) ammonium & sulfite ions
• IONS:
NH4+ & SO3 2NH4+
• FORMULA: (NH4)2SO3
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Practice Problems, cont.
from p 16 2of text
3b)
3c)
3d)
4a)
4b)
4c)
4d)
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Transition Metals
• QUESTION: What was strange
about the e- configurations of
transition metals?
ANSWER: Their d sublevels
overlap with the other
sublevels in the next higher
main E.L.
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Oxidation #s of Transition Metals
• The d sublevel e-s are so close to the
actual valence e-s, they sometimes act
like valence e-s!
• See Table 5.4 on p 164 of text:
Common Ions of Select Transition
Metals
• Ex: Fe 2+ & Fe 3+
• Write the e- configuration
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e- Configuration for Fe
•Fe=26 e-s
2
2
6
2
6
2
6
•1s 2s 2p 3s 3p 4s 3d
2
•Valence e-s=4s
BUT,
some
3d
e-s
can
be
lost
•
too!
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Writing Formulas for Ionic Cpds
containing Transition Metals
1. Identify the cation & anion
2. Determine the oxidation #s on the
cation & anion
–The oxidation # of the cation is given
in the name ex: Nickel (IV) = Ni4+
–The Roman numeral is the oxidation#
3. Write a formula w/ 0 charge.
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Distillation
• Def: process of separating ionic &
covalent compounds by heating
them till the covalent compound
evaporates.
– The ionic compound remains in the
flask
– The covalent compound can be
cooled & collected in a separate
container.
– This process is called distillation
Learning Check
Match each set with the correct name:
A.
Na2CO3
1) magnesium sulfite
MgSO3
2) magnesium sulfate
MgSO4
3) sodium carbonate
B.
Ca(HCO3)2
CaCO3
1) calcium carbonate
2) calcium phosphate
Ca3(PO4)2
3) calcium bicarbonate
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Solution
A.
B.
Na2CO3
MgSO3
3) sodium carbonate
1) magnesium sulfite
MgSO4
2) magnesium sulfate
Ca(HCO3)2
3) calcium bicarbonate
CaCO3
1) calcium carbonate
Ca3(PO4)2
2) calcium phosphate
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Learning Check
A. aluminum nitrate
1) AlNO3
2) Al(NO)3
3) Al(NO3)3
B. copper(II) nitrate
1) CuNO3
2) Cu(NO3)2
3) Cu2(NO3)
C. Iron (III) hydroxide
1) FeOH
2) Fe3OH
3) Fe(OH)3
D. Tin(IV) hydroxide
1) Sn(OH)4
2) Sn(OH)2
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Solution
A. aluminum nitrate
3) Al(NO3)3
B. copper(II) nitrate
2) Cu(NO3)2
C. Iron (III) hydroxide
3) Fe(OH)3
D. Tin(IV) hydroxide
1) Sn(OH)4
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