Chemistry 11
Unit 9 Chemical Bonding #2
Name:____________________________
Block:_________
Types of bonding
There are three types of bond that can occur between atoms:
 an
occurs between a
 a
occurs between
 a
and
atom (e.g. NaCl)
atoms (e.g. I2, CH4)
occurs between atoms in a
(e.g. Cu)
Ionic bonding
Charge on the ions
Metals
to form
ions (
) while non-metals
electrons to form
ions.(
)
The number of electrons gained or lost by an atom is related to the group in which the element is found.
The elements in groups 4 and 8
(also called group 0)
gain or lose electrons to
form ionic compounds.
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Representing ionic bonding
Covalent bonding
How are Covalent Bonds Formed?
2
Metallic bonding
Strength of metallic bonding: ion charge
The strength of metallic bonding depends on two factors:
1.
2.
3
1. The charge on the metal ions
2. The size of the metal ions
The
on the
The
the metal ion, the
metal ions, the
closer the positive nucleus is to the delocalized
between the ions and the
electrons.
electrons, and the
the
This means there is a
metallic bonds.
between the two, which creates a
A
is
metallic bond.
evidence of stronger bonds in the substance.
What are bonds?
Each element is made up of just one type of atom, usually joined to other atoms of the same element by
.
Why do atoms form bonds?
Bonds involve the
in the outer shells of atoms.
The atoms of noble gases have
outer shells and so are
This makes the noble gases very
.
and so they do not usually form bonds.
The atoms of other elements have
outer electron shells and so are
.
By
, the atoms of these elements are able to have filled outer shells
and become stable.
What are the types of bonding?
 i
bonding
– occurs between
 c
and
atoms.
bonding
4
– occurs between
 m
atoms only.
bonding
– occurs between metal atoms only.
All bonds involve
and all bonding involve changes to the number of electrons in
the outer shells of atoms.
ASSIGNMENT #2A: answer Hebden Questions on a Separate Page
Pg. 172 #57
4. Complete the Following Table:
How do atoms form ions?
Atoms have an
number of protons and electrons and so do not have an overall charge.
Atoms with
outer electron shells are
By either
or
.
electrons, atoms can obtain full outer
electron shells and become stable.
An atom that
so has a
This is called a
has more protons than electrons and
overall charge.
.(or cation)
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An atom that
has more electrons than protons and
so has a
overall charge.
This is called a negative ion.(or anion)
The
of an atom shows how many electrons it must lose
or gain to have a filled outer shell.
How do atoms form positive ions?
An atom that
one or more electrons forms a positive ion.
, such as sodium, magnesium and iron, form positive ions.
How is a sodium ion formed?
(draw the diagram below)
How do atoms form negative ions?
An atom that
one or more electrons forms a negative ion.
Non-metal atoms, such as chlorine, oxygen and nitrogen, form negative ions.
(draw the diagram below)
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Calculating ion charges
Electron configuration of ions
When
gain or lose electrons to complete their outer
electron shell, they can create ions that have the
.
Draw the example of oxygen and fluorine:
oxygen and fluorine
The number of
to become negative ions
and
however, remain different for each element.
This means that each ion has different
.
What is a Polyatomic ion?
Ions can be made up of a single
atom or a
.
An ion made up of a group of atoms
is called a
ion.
What is ionic bonding?
Compounds that contain ions are called
. These compounds are
usually formed by a reaction between a
and a
The metal and non-metal atoms have incomplete outer electron shells and so are
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.
.
Electrons are
from each metal atom to each non-metal atom.
The metal and the non-metal atoms form ions with
become
outer shells and
.
The positive and negative ions are
to each other.
This
attraction is called ionic bonding.
How are ionic bonds formed?
Sodium chloride is an ionic compound formed by the reaction between the metal sodium and the nonmetal chlorine.
The
sodium ions and the
chloride ions are strongly
attracted to each other.
It is this
attraction that forms ionic bonds in sodium chloride and other ionic
compounds.
What is the ratio of ions?
Sodium chloride (NaCl) and magnesium oxide (MgO) are
In each compound, the metal needs to lose the
ionic compounds.
that the
non-metal needs to gain.
Both compounds have a
of
metal ions to non-metal ions, which is shown by
the formula of each compound.
Sodium (2.8.1) needs to
sodium ion but oxygen (2.6) must
form an oxide ion .
8
to form a
to
sodium atoms are required for each oxygen atom and so the ratio of sodium ions to oxide
ions is
.
From this ratio, the formula of sodium oxide is
What is the ratio of ions needed for magnesium chloride?(draw the diagram, and indicate the ratio)
How to write the formula of an ionic compound
1.
2.
3.
4.
What is the formula of aluminium bromide?
What is the formula of aluminium oxide?
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ASSIGNMENT #2B: Complete the formulae of all the possible ionic compounds from combinations of these
metals and non-metals.
Properties of Ionic Compounds
What is an ionic lattice?
In an
, when any macroscopic sample ions react together, countless
atoms will transfer electrons to form countless
ions.
These oppositely charged species being produced in close proximity are drawn together into an giant, 3D,
ordered, solid, three-dimensional array of cations and anions called a
.
The
in this structure
represents the
for the ionic compound
The structure of the ionic lattice
of the ionic compound.
compounds form
and crystals when
Heating ionic compounds
Why are ionic compounds solid at room temperature and have
high melting points and boiling points?
Ionic bonds are
and a lot of heat is
needed to break them.
produce
ionic
so much more heat is required to break the ionic bonds in magnesium oxide than in sodium chloride.
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and
How can ionic compounds conduct electricity?
As
, ionic compounds
because their ions are bonded
together in the lattice.
When
(molten), the ions can break
free of the lattice and are able to move.
The
and so
can carry an
.
Ionic compounds are usually
in water because water molecules have a slight
charge and so can
the ions away from the lattice.
, the ions are free to move and can carry an electric current.
Why are ionic compounds brittle?
Ionic compounds are brittle – they shatter when they are hit.
Ionic bonds are strong, so why does this happen?
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Assignment 2C: answer Hebden Questions on a Separate Page
Pg. 173 #58-59
61
pg 175 #62-64
WORKSHEET #1
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WORKSHEET #2
13
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