INTRODUCTION TO
BONDING
CHEMICAL BONDING
CHEMICAL BOND
• ATTRACTIVE FORCE BETWEEN ATOMS OR IONS THAT
BINDS THEM TOGETHER AS A UNIT
• BONDS FORM IN ORDER TO…
• DECREASE POTENTIAL ENERGY (PE)
• INCREASE STABILITY
BONDS ARE…
 FORCES THAT HOLD GROUPS OF
ATOMS TOGETHER AND MAKE THEM
FUNCTION AS A UNIT. TWO TYPES:
1) Ionic
bonds – transfer of electrons
(gained or lost; makes formula unit)
2) Covalent
bonds – sharing of
electrons. The resulting particle is
called a “molecule”
TYPES OF BONDS
IONIC
COVALENT
Bond
Formation
e- are transferred from
metal to nonmetal
e- are shared between
two nonmetals
Type of
Structure
crystal lattice
true molecules
Physical
State
solid
liquid or gas
Melting
Point
high
low
Solubility in
Water
yes
usually not
Electrical
Conductivity
yes
(solution or liquid)
no
Other
Properties
odorous
TYPES OF BONDS
METALLIC
Bond
Formation
e- are delocalized
among metal atoms
Type of
Structure
“electron sea”
Physical
State
solid
Melting
Point
very high
Solubility in
Water
no
Electrical
Conductivity
yes
(any form)
Other
Properties
malleable, ductile,
lustrous
VALENCE ELECTRONS ARE…?
THE s AND p ELECTRONS IN THE OUTER
ENERGY LEVEL OR THE HIGHEST
OCCUPIED ENERGY LEVEL.
THE ELECTRONS RESPONSIBLE FOR THE
CHEMICAL PROPERTIES OF ATOMS.
ELECTRON DOT DIAGRAMS ARE…
• A WAY OF SHOWING & KEEPING TRACK
OF VALENCE ELECTRONS.
• HOW TO WRITE THEM?
• WRITE THE SYMBOL - IT REPRESENTS THE
NUCLEUS AND INNER (CORE) ELECTRONS
• PUT ONE DOT FOR EACH VALENCE
ELECTRON (8 MAXIMUM)
• THEY DON’T PAIR UP UNTIL THEY HAVE
TO (HUND’S RULE)
X
The Electron Dot diagram for Nitrogen
Nitrogen has 5 valence
electrons to show.
 First we write the symbol.

Then
add 1 electron at a
time to each side.
Now they are forced to pair up.
N
We have now written the electron dot
diagram for Nitrogen.
The Octet Rule
In Chapter 6, we learned that noble gases are
unreactive in chemical reactions
 In 1916, Gilbert Lewis used this fact to explain
why atoms form certain kinds of ions and
molecules
 The Octet Rule: in forming compounds, atoms
tend to achieve a noble gas configuration; 8 in
the outer level is stable


Each noble gas (except He, which has 2) has 8
electrons in the outer level
OCTET RULE
• METALS LOSE ELECTRONS TO ATTAIN A NOBLE GAS
CONFIGURATION. FORM CATIONS (POSITIVE)
• NONMETALS GAIN ELECTRONS TO ATTAIN NOBLE
GAS CONFIGURATION. FORM ANIONS (NEGATIVE)
• AN ATOM IS ELECTRICALLY NEUTRAL BECAUSE THE
PROTONS AND ELECTRONS ARE EQUAL, IONS FORM
WHEN THEY LOSE OR GAIN ELECTRONS.
IONIC NOMENCLATURE
COMMON ION CHARGES
1+
0
2+
3+ NA 3- 2- 1-
IONIC NOMENCLATURE
IONIC FORMULAS
• WRITE EACH ION, CATION FIRST. DON’T SHOW
CHARGES IN THE FINAL FORMULA.
• OVERALL CHARGE MUST EQUAL ZERO.
• IF CHARGES CANCEL, JUST WRITE SYMBOLS.
• IF NOT, USE SUBSCRIPTS TO BALANCE CHARGES.
• USE PARENTHESES TO SHOW MORE THAN ONE
POLYATOMIC ION.
• STOCK SYSTEM - ROMAN NUMERALS INDICATE THE
ION’S CHARGE.
IONIC NOMENCLATURE
IONIC NAMES
• WRITE THE NAMES OF BOTH IONS, CATION FIRST.
• CHANGE ENDING OF MONATOMIC IONS TO -IDE.
• POLYATOMIC IONS HAVE SPECIAL NAMES.
• STOCK SYSTEM - USE ROMAN NUMERALS TO SHOW THE
ION’S CHARGE IF MORE THAN ONE IS POSSIBLE. OVERALL
CHARGE MUST EQUAL ZERO.
IONIC NOMENCLATURE
• CONSIDER THE FOLLOWING:
• DOES IT CONTAIN A POLYATOMIC ION?
• -IDE, 2 ELEMENTS  NO
• -ATE, -ITE, 3+ ELEMENTS  YES
• DOES IT CONTAIN A ROMAN NUMERAL?
• CHECK THE TABLE FOR METALS NOT IN
GROUPS 1 OR 2.
• NO PREFIXES!
IONIC NOMENCLATURE
potassium chloride

K+ Clmagnesium nitrate
Mg2+ NO3
copper(II) chloride
Cu2+ Cl-

KCl
Mg(NO3)2
CuCl2
IONIC NOMENCLATURE
NaBr
sodium bromide
Na2CO3
sodium carbonate
FeCl3
iron(III) chloride
MOLECULAR COMPOUNDS
CHEMICAL BONDING
LEWIS STRUCTURES
• OCTET RULE
• MOST ATOMS FORM BONDS IN ORDER TO OBTAIN 8
VALENCE E• FULL ENERGY LEVEL STABILITY ~ NOBLE GASES
Ne
LEWIS STRUCTURES
•
NONPOLAR COVALENT - NO CHARGES
•
POLAR COVALENT - PARTIAL CHARGES
+
+
MOLECULAR NOMENCLATURE
• PREFIX SYSTEM (BINARY COMPOUNDS)
1. LESS E-NEG ATOM COMES FIRST.
2. ADD PREFIXES TO INDICATE # OF ATOMS. OMIT MONO- PREFIX
ON FIRST ELEMENT.
3. CHANGE THE ENDING OF THE SECOND ELEMENT TO -IDE.
MOLECULAR NOMENCLATURE
PREFIX
MONODITRITETRAPENTAHEXAHEPTA-
OCTANONADECA-
NUMBER
1
2
3
4
5
6
7
8
9
10
MOLECULAR NOMENCLATURE
CCl4
carbon tetrachloride
N2O
dinitrogen monoxide
SF6
sulfur hexafluoride
MOLECULAR NOMENCLATURE
arsenic trichloride
AsCl3
dinitrogen pentoxide
N 2O 5
tetraphosphorus decoxide
P4O10
MOLECULAR NOMENCLATURE
• THE SEVEN DIATOMIC ELEMENTS
BR2 I2 N2 CL2 H2 O2 F2
H
N O F
Cl
Br
I