Intramolecular forces describe bonds that hold atoms
together to create molecules and compounds
• Bonding between atoms is a result of the atoms
competing for electrons to get full valence shells
• Bonding between atoms can occur by two atoms sharing
electrons to form covalent bonds, or by transferring and
accepting electrons to form ionic bonds
Ionic bond describes the force holding charged particles
together in ionic compounds
Na
loses an e-
Cl
Na+
Cl-
gains an e-
Na+-Cl- Ionic bond is an electrostatic attraction between
oppositely charged atoms
An ionic bond is formed by the ________________________
from a metal to a nonmetal
• Metal atom always ________ or ______________
electron(s) to become a ___________________
• Nonmetal atom always __________ or __________
electron(s) to become a ___________________
• Ionic bond is formed by the electrostatic attraction
between the positive metal ion and the negative nonmetal
ion
• Electronegativity difference between the nonmetal and the
metal atom in ionic bonds is usually 1.7 or greater
Example of substances containing ionic bonds
NaCl
sodium chloride
CaF2
calcium fluoride
Fe2O3
iron oxide
Covalent bond describes the force holding atoms of
nonmetals together in covalent and molecular substances
H
Cl
H-Cl
Covalent bond forms between H and Cl atoms. A (-)
between two nonmetal atoms represents two (a pair) shared
electrons
Covalent bonding occurs between two nonmetal atoms
that are _________________ electrons
• Electronegativity difference between the two
nonmetals in a covalent bond is usually less than 1.7
• Electronegativity difference between 0 and 0.4
indicates a nonpolar covalent bond
• Electronegativity difference between 0.5 and 1.6
indicates a polar covalent bon
• Nonpolar covalent bond = equal sharing of electrons
• Polar covalent bond = unequal sharing of electrons
Examples of substances containing covalent bonds
H2O
water
CO2
carbon dioxide
SiC
silicon carbide
H2
diatomic hydrogen molecule
There are four types of covalent bonding
• Polar covalent bond – unequal sharing of electrons
between two different nonmetal atoms (electronegativity
difference 0.5 – 1.6; examples H2O, HCl, NH3)
• Nonpolar covalent bond – equal sharing of electrons
between two nonmetal atoms (sometimes the same
atoms) (electronegativity difference 0 – 0.4; examples H2,
N2)
• Network covalent bond – formed between nonmetal
atoms in network solid compounds; compounds formed by
network bonding cannot exist as an individual molecule
(examples C diamond, SiO2, SiC)
• Coordinate covalent bond – formed when both shared
electrons are provided by ONLY one of the atoms (H+ does
not have an electron but bonds with a molecule such as NH3
ammonia or H2O that have a lone pair (two unbonded)
electrons that they can share with a H+ in that doesn’t have
any electron
Examples NH4+ ammonium ion formed from NH3 and H+
H3O+ hydronium ion formed from H2O and H+
• Metallic bond – force that holds metal atoms together in
metallic substances; positive ions immersed in sea of mobile
valence electrons; mobile electrons allow for high electrical
conductivity in metals
Examples Ca
Au
Fe
Electronegativity
difference
Type of
substances
containing
bond
Example
formulas
containing
bond
Positive ions in
sea of
electrons
_________
Metallic
substances
Ag
K
Metal +
nonmetal
Transfer of
electrons
1.7 or greater
Ionic
substances
NaCl
Li2O
Covalent
Nonmetals
only
Sharing of
electrons
Less than 1.7
Molecular
substances
HCl
Polar
covalent
Two different
nonmetals
Unequal
sharing
0.5 – 1.6
Polar and
nonpolar
substance
H2O
CH4
Nonpolar
covalent
Same nonmetal
or nonmetal
atoms with
similar
electronegativity
Equal sharing
of electrons
0 – 0.4
Nonpolar
substances
H2
O2
Coordinate
covalent
Two different
nonmetals
One atom
provides both
shared
electrons
_________
Polyatomic
ions
NH4+
H3O+
Network solid
covalent
Nonmetals
only
No discrete
particies
_________
Network solids
C, SiC, SiO2
Bond Type
Type of
elements
involved in
bonding
Bond
Metallic
metal atoms of
the same
element
Ionic
description
Determining type of bonding between atoms
To determine formula containing
• Ionic bond
LOOK for a formula or name containing a metal and a nonmetal
• Covalent bond
LOOK for a formula or name containing only nonmetal atoms
• Polar covalent bonds
LOOK for a formula or name containing two different nonmetals
• Nonpolar covalent bonds
LOOK for a diatomic formula
• Metallic bond
LOOK for a symbol of a metallic element
• Both ionic and covalent bonds
LOOK for a formula containing at least three different elements
or a polyatomic ion