3.1 Introduction to Bonding
• Metals
• left side of per. table
• less than 4 valence e• low ionization energy
• large atoms
• e- far nucleus
• e- weakly held
• e- easy to remove
• lose electrons
• undergo oxidation
• form cations (+ charge)
Nonmetals
right side of per. Table
more than 4 valence ehigh ionization energy
small atoms
e- close to nucleus
e- tightly held
e- hard to remove
gain electrons
undergo reduction
form anions (- charge)
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3.1 Introduction to Bonding (1)
Bonding is the joining of two atoms in a stable
arrangement.
Elements will gain, lose, or share electrons to
reach the electron configuration of the noble gas
(octet) closest to them in the periodic table.
There are two different kinds of bonding:
• Ionic bonds result from the transfer of electrons
from one element to another.
• Covalent bonds result from the sharing of
electrons between two atoms.
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3.1 Introduction to Bonding (1)
There are two different kinds of bonding:
• Ionic bonds
• Result from the transfer of electrons from one element to another
• Formed between metals and nonmetals
• Forms particles called ions; metals for cations, nonmetals for
anions
• Bonding force is the result of the attraction oppositely charged
particles
• Covalent bonds
•
•
•
•
Result from the sharing of electrons between two atoms
Formed between two nonmetals
Forms particles called molecules
Bonding force is a result of the shared electrons orbiting the
nuclei of both atoms
3
Ion Charges by Group
+1
+2
polyvalent +1, +2, or +3
+3
+4
-3
-2
-1
0
4
3.2 Ions (9)
5
3.2 Ions (10)
C. Metals with Variable Charge
6
3.4 Naming Ionic Compounds (3)
A. Naming Cations
Table 3.3 Systematic and Common Names for Some Metal Ions
Element
Ion Symbol
Systematic Name
Common Name
Chromium
Cr 2+
Chromium(II)
Chromous
Chromium
Cr 3+
Chromium(III)
Chromic
Copper
Cu+
Copper(I)
Cuprous
Copper
Cu2+
Copper(II)
Cupric
Iron
Fe 2+
Iron(II)
Ferrous
Iron
Fe 3+
Iron(III)
Ferric
Mercury
Hg 2+
2
Mercury(I)a
Mercurous
Mercury
Hg 2+
Mercury(II)
Mercuric
Tin
Sn2+
Tin(II)
Stannous
Tin
Sn4+
Tin(IV)
Stannic
aMercury(I) exists as Hg 2+ , containing two atoms of mercury, each with a +1 charge.
2
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3.4 Naming Ionic Compounds (4)
B. Naming Anions
Anions are named by replacing the ending of the
element name by the suffix “-ide.”
Table 3.4 Names of Common Anions
Element
Ion Symbol
Name
Bromine
Br −
Bromide
Chlorine
Cl−
Chloride
Fluorine
F−
Fluoride
Iodine
I−
Iodide
Nitrogen
N 3−
Nitride
Oxygen
O2−
Oxide
Phosphorus
P 3−
Phosphide
Sulfur
S 2−
Sulfide
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3.4 Naming Ionic Compounds (9)
E. Writing a Formula from the Name
HOW TO Derive a Formula from the Name of an Ionic
Compound
Compound
Example
Write the formula for tin(IV) oxide.
Step [1]
Identify the cation and anion and
determine their charges. For metals
with variable charges, the Roman
numeral gives the charge on the cation.
tin(IV) oxide
𝐎𝟐−
𝐒𝐧𝟒+
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3.4 Naming Ionic Compounds (10)
E. Writing a Formula from the Name
HOW TO Derive a Formula from the Name of an Ionic
Compound
Compound
Step [2]
Balance charges.
𝐒𝐧𝟒+
Step [3]
𝐎𝟐−
Two −𝟐 anions
are needed for
each +𝟒 cation.
Write the formula with the cation first, and
use subscripts to show how many of each
ion is needed to have zero overall charge.
final answer = 𝐒𝐧𝐎𝟐
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3.6 Polyatomic Ions (1)
A polyatomic ion is a cation or anion that contains more than one atom.
Nonmetal
Formula
Name
Carbon
(CO3) 2-
Carbonate
HCO3 1
−
(C2H3 O2) 2
Hydrogen carbonate or bicarbonate
−
Acetate
(CN) 1-
Cyanide
(NO3) 1-
Nitrate
(NO2) 1-
Nitrite
Oxygen
𝐎𝐇 𝟏−
Hydroxide
Phosphorus
(𝐏𝐎𝟒 ) 3-
Phosphate
(𝐇𝐏𝐎𝟒 ) 2-
Hydrogen phosphate
(SO4) 2-
Sulfate
(HSO4) 1-
Hydrogen sulfate or bisulfate
(SO3) 2-
Sulfite
(HSO3) 1-
Hydrogen sulfite or bisulfite
Nitrogen
Sulfur
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3.6 Polyatomic Ions (2)
A. Writing Formulas for Ionic Compounds with
Polyatomic Ions
Writing formulas for ionic compounds with
polyatomic ions is the same as writing formulas
for ions with single charged atoms. (Section 3.3A)
When a cation and anion of equal charge combine,
only one of each ion is needed.
− →
+𝟏
𝟏
𝑵𝒂
(𝑵𝑶𝟐)
𝑵𝒂(𝑵𝑶𝟐 )
1
𝑩𝒂
1
𝟐+
2
(𝑺𝑶𝟒
zero overall
charge
−→
𝟐
)
𝑩𝒂(𝑺𝑶
2
𝟒)
zero overall
charge
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3.6 Polyatomic Ions (3)
A. Writing Formulas for Ionic Compounds with
Polyatomic Ions
When a cation and anion of unequal charge
combine, use the ionic charges to determine
the relative number of each ion that is needed.
𝑴𝒈𝟐+ (𝑶𝑯)− 𝟏 → 𝑴𝒈𝟏 𝑶𝑯 𝟐
+𝟐 charge means
2 𝐎𝐇 − anions are
needed.
−𝟏 charge means
1 𝐌𝐠 𝟐+ anion is
needed.
zero overall
charge
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3.6 Polyatomic Ions (4)
B. Naming Ionic Compounds with Polyatomic Ions
The same rules are followed for naming standard
ionic compounds:
Name the cation and then the anion.
Do not specify the charge on the ions.
Do not specify how many ions of each type are
needed to balance charge.
𝐍𝐚(𝐇𝐂𝐎𝟑 )
𝐍𝐚
+𝟏
(𝐇𝐂𝐎𝟑 )-1
sodium bicarbonate
𝐀𝐥𝟐 𝐒𝐎𝟒 𝟑
Al+3 (SO4)2aluminum sulfate
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3.6 Polyatomic Ions (4)
B. Naming Ionic Compounds with Polyatomic Ions
Sodium sulfide
Na+1 S2-
= Na2S
Calcium hydroxide Ca2+ (OH)1-
= Ca(OH)2
Aluminum nitrate Al3+ (NO3)1-
= Al(NO3)3
Magnesium bicarbonate Mg2+ (𝐇𝐂O3) 1- =
Mg(𝐇𝐂O3)2
Iron (III) sulfate
𝐍𝐚
+𝟏
(𝐇𝐂𝐎𝟑 )-1
Fe3+
𝐒𝐎𝟒
𝟐−
=
Fe2 𝐒𝐎𝟒 𝟑
Al+3 (SO4)2-
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4.1 Introduction to Covalent Bonding (3)
A. Covalent Bonding and the Periodic Table
Lewis structures are electron-dot structures for
molecules. They show the location of all valence 𝐞− .
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4.2 Lewis Structures (8)
B. Multiple Bonds
One lone pair of 𝐞− can be converted into one
bonding pair of 𝐞− for each 2 𝐞− needed to
complete an octet on a Lewis Structure.
A double bond contains four electrons in two 2
𝐞− bonds.
A triple bond contains six electrons in three 2 𝐞−
bonds.
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4.5 Naming Covalent Compounds (3)
HOW TO Name a Covalent Molecule
Table 4.1 Common Prefixes
in Nomenclature
Number
of Atoms
Prefix
1
Mono
2
Di
3
Tri
4
Tetra
5
Penta
6
Hexa
7
Hepta
8
Octa
9
Nona
10
Deca
a) 𝐍𝐎𝟐
mononitrogen dioxide
or
Nitrogen dioxide
b) 𝐍𝟐 𝐎𝟒
dinitrogen tetroxide
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Types of Reactions
(A, B = METALS or CATIONS;
X, Y = NONMETALS or ANIONS)
COMPOSITION
A + X → AX
DECOMPOSITION
AX → A + X
SINGLE REPLACEMENT
AX + B → BX + A
AY + X → AX + Y
DOUBLE REPLACEMENT
AX + BY → AY + BX
or
COMBUSTION CXHY + OXYGEN → CARBON DIOXIDE + WATER
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3 Steps to Complete a Balanced Formula
Equation when given the Reactants
(A, B = METALS or CATIONS;
1.
X, Y = NONMETALS or ANIONS)
Complete the word equation by matching the reactants to one of the general
types of reactions:
1.
2.
3.
4.
5.
COMPOSITION
A + X → AX
DECOMPOSITION
AX → A + X
SINGLE REPLACEMENT
AX + B → BX + A
or
AY + X → AX + Y
DOUBLE REPLACEMENT AX + BY → AY + BX
COMBUSTION C XHY + OXYGEN → CARBON DIOXIDE + WATER
2. Write the correct symbols and formulas for each substance.
For elements check for the seven diatomics H2, N2, O2, F2, Cl2, Br2, and I2.
For compounds use the ion-charge method to write the correct formula.
3.
Balance the equation.
Adjust the coeficients in front of each substance to get the same number of
each type of atom on both sides of the equation.
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