Ionic Bonding
Writing Formulae
Naming Compounds
Atoms and Ions
Bond —force that holds 2
atoms together
 Atoms are neutral=same number of
protons as electrons
 Ion—atom that has lost or gained
electrons (it has a charge of + or -)
 Chemical
Remember
 Only
electrons can
move
 Atoms gain or lose
electrons to achieve
a noble gas
configuration
 To be stable
Keeping Track of Electrons
 The
electrons responsible for the
chemical properties of atoms are
those in the outer energy level.
 Valence electrons - The s and p
electrons in the outer energy level.
 Core electrons -those in the energy
levels below.
Keeping Track of Electrons
 Atoms
in the same column have
the same outer electron
configuration.
 Have the same valence electrons.
 Easily found by looking up the
group number on the periodic table.
 Group 2A - Be, Mg, Ca, etc. 2 valence electrons
Electron Dot diagrams
A way of keeping track of
valence electrons.
 How to write them
 Write the symbol.
 Put one dot for each
valence electron
 Don’t pair up until they
have to

X
The Electron Dot diagram for
Nitrogen
Nitrogen has 5 valence
electrons.
 First we write the symbol.
Then add 1 electron at a
time to each side.
Until they are forced to pair up.

N
Write the electron dot diagram
for
Na
 Mg
C
O
F
 Ne
 He

Electron Configurations for
Cations
Metals lose electrons to attain noble gas
configuration.
 They make positive ions.
 If we look at electron configuration it
makes sense.
 Na 1s22s22p63s1 - 1 valence electron
 Na+ 1s22s22p6 -noble gas configuration

Electron Dots For Cations

Metals will have few valence electrons
Ca
Electron Dots For Cations
Metals will have few valence electrons
 These will come off

Ca
Electron Dots For Cations
Metals will have few valence electrons
 These will come off
 Forming positive ions

+2
Ca
Electron Configurations for
Anions *
Nonmetals gain electrons to attain noble
gas configuration.
 They make negative ions.
 If we look at electron configuration it
makes sense.
 S 1s22s22p63s23p4 - 6 valence electrons
 S-2 1s22s22p63s23p6 -noble gas
configuration.

Electron Dots For Anions
Nonmetals will have many valence
electrons.
 They will gain electrons to fill outer shell.

P
-3
P
Stable Electron Configurations
All atoms react to achieve noble gas
configuration.
 Noble gases have 2 s and 6 p electrons.
 8 valence electrons .
 Also called the octet rule.

Ar
Compounds
2 atoms bonded
together
 Follow the Law of
Definite Proportion—
have a constant
composition—the
same # of atoms
every time

3 Types of compounds
Ionic
Bonds
Covalent or Molecular
Bonds
Metallic Bonds
Ionic Bonds
Made by transferring electrons
 Made of cations (metals) and anions
(nonmetals)
 The e- lost by the cation is gained by
the anion
 The cations and anions surround each
other
 Smallest piece is a Formula Unit

Ionic Bonding
Ionic Bonding
Anions and cations are held together by
opposite charges.
 Packed into a regular repeating pattern
that balances the forces of attraction
and repulsion between the ions forming
a crystal
 Very strong bond
 Ionic compounds are called salts.

Properties of Ionic Compounds
Crystalline structure.
 A regular repeating arrangement of ions
in the solid.
 Ions are strongly bonded.
 Structure is rigid.
 High melting points- because of strong
forces between ions.

Crystalline structure
Do they Conduct?
Conducting electricity is allowing charges
to move.
 In a solid, the ions are locked in place.
 Ionic solids are insulators.
 When melted, the ions can move around.
 Melted ionic compounds conduct.
 First get them to 800ºC.
 Dissolved in water they conduct.

Ionic solids are brittle
+
+
-
+
+
+
+
-
+
+
Ionic solids are brittle

Strong Repulsion breaks crystal apart.
- + - +
+ - + - + - +
Writing the formula for
compounds and Naming
compounds
Learning to speak the language
Chemical Formula
 Shows
the kind
and number of
atoms in the
smallest piece
of the
substance
 Nicotine

C10H14N2
For Ionic Compounds:
Systematic Naming
There are too many compounds to
remember the names of them all
 Compound-2 or more elements
chemically combined
 Pure substance
 Name tell how many and what kind of
atoms

Remember –Ionic Bonds
Anions and cations held together by
opposite charges
 Called salts
 Simplest ratio is called formula unit
 Bond is formed by transfer of electrons
 Electrons are transferred to achieve a
noble gas configuration

Ionic bonding or Formula Unit
 Shows
lowest
whole # ratio
of atoms in
the crystal
lattice
 NaCl
 MgCl2
Charges on Ions
You can tell charge of an atom by its
location
 Elements in the same group have
similar properties including the charge
when they are ions
 Oxidation number -the charge of the ion

+1
+2
+3
-3 -2 -1
Naming ions
We will use the systematic way.
 Cation- if the charge is always the same
(Group A) just write the name of the
metal.
 Transition metals can have more than
one type of charge.
 Indicate the charge with roman
numerals in parenthesis.

Name these
Na+1
 Ca+2
 Al+3
 Fe+3
 Fe+2
 Pb+2
+1
 Li

Write Formulas for these
Potassium ion
 Magnesium ion
 Copper (II) ion
 Chromium (VI) ion
 Barium ion
 Mercury (II) ion

Naming Anions
Anions are always the same.
 Change the element ending to – ide
 F-1 Fluorine

Naming Anions
Anions are always the same.
 Change the element ending to – ide
 F-1 Fluorine  Fluor + ide =

Fluoride
Name these

Cl-1

N-3
Br-1
-2
O
 Ga+3

Write these
Sulfide ion
 iodide ion
 phosphide ion
 Strontium ion

Polyatomic ions
Group of atoms covalently bonded together
that gain or lose an electron
 LEARN YOU POLYATOMIC IONS!
 Oxyanion –polyatomic ions composed of an
element bonded to one or more oxygen
atoms
– Ate ions
– Ite ions
– Per
– hypo

Polyatomic ions

Sulfate SO4-2

Sulfite SO3-2

Carbonate CO3-2
Chromate CrO4-2
 Dichromate

Cr2O7-2
Phosphate PO4-3
 Phosphite PO3-3


Ammonium NH4+1
Monatomic vs Polyatomic anions
 S-2
monatomic
 Sulfide ion
 N-3 monatomic
 Nitride ion
 Bromide
 Selenide
 SO4-2
polyatomic
 Sulfate ion
 NO3- polyatomic
 Nitrate
 PO4-3
 Phosphate ion
Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
 Ionic - a cation and an anion.
 To write the names just name the two
ions.
 Easy with Representative elements.
 Group A
 NaCl = Na+ Cl- = sodium chloride
 MgBr2 = Mg+2 Br- = magnesium bromide

Naming Binary Ionic Compounds
The problem comes with the transition
metals.
 Need to figure out their charges.
 The compound must be neutral.
 same number of + and – charges.
 Use the anion to determine the charge
on the positive ion.

Naming Binary Ionic
Compounds
Write the name of CuO
 Need the charge of Cu
 O is -2
 copper must be +2
 Copper (II) chloride
 Name CoCl3
 Cl is -1 and there are three of them = -3
 Co must be +3 Cobalt (III) chloride

Naming Binary Ionic Compounds
Write the name of Cu2S.
 Since S is -2, the Cu2 must be +2, so
each one is +1.
 copper (I) sulfide
 Fe2O3
 Each O is -2
3 x -2 = -6
 3 Fe must = +6, so each is +2.
 iron (III) oxide

Naming Binary Ionic Compounds
Write the names of the following
 KCl
 Na3N
 CrN

Sc3P2
 PbO

PbO2
 Na2Se

Ternary Ionic Compounds
Will have polyatomic ions
 At least three elements
 name the ions
 NaNO3

 CaSO4
 CuSO3
 (NH4)2O
Ternary Ionic Compounds
LiCN
 Fe(OH)3
 (NH4)2CO3
 NiPO4

Writing Formulas
 The
charges have to add up to
zero.
 Get charges on pieces.
 Cations from name on table.
 Anions from table (ide) or
polyatomic.
 Balance the charges by using
subscripts.
Ionic Bonding
Na Cl
Ionic Bonding
+
Na
Cl
-
Ionic Bonding

All the electrons must be accounted for!
Ca
P
Ionic Bonding
Ca
P
Ionic Bonding
+2
Ca
P
Ionic Bonding
+2
Ca
Ca
P
Ionic Bonding
+2
Ca
Ca
P
-3
Ionic Bonding
+2
Ca
P
Ca
P
-3
Ionic Bonding
+2
Ca
P
+2
Ca
P
-3
Ionic Bonding
Ca
+2
Ca
P
+2
Ca
P
-3
Ionic Bonding
Ca
+2
Ca
P
+2
Ca
P
-3
Ionic Bonding
+2
Ca
+2
Ca
+2
Ca
P
P
-3
-3
Ionic Bonding
Ca3P2
Formula Unit
Writing Formulas
 Write
the formula for calcium chloride.
 Calcium is Ca+2

Chloride is Cl-1
 Ca+2 Cl-1
would have a +1 charge.
 Need another Cl-1
 Ca+2 Cl2-1
 CaCl2
1 (+2) and 2 (-1)=0
Write the formulas for these
Lithium sulfide
 tin (II) oxide
 tin (IV) oxide
 Magnesium fluoride
 Iron (III) phosphide
 Iron (III) sulfide

Writing Ternary Ionic
Write the formula for calcium chlorate.
 Calcium is Ca+2
Chlorate is ClO3-1
 Ca+2 ClO3-1
 Need another ClO3-1
 When you need to have more than one
polyatomic ion you must use
PARENTHESES
 Ca(ClO3) 2

Write the Formula
Lithium sulfate
 tin (II) hydroxide
 tin (IV) cyanide
 Magnesium dichromate
 Iron (III) Phosphate
 Iron (III) sulfide
