PDP Chemistry
Bonding
Topic 3: Bonding
• ionic bonding
• covalent bonding
Ionic bonding between
metals and non-metal atoms
Ionic compounds
positive and negative ion
usually:
 positive ion from a metal (cation)
 negative ion from a non-metal (cation)
Iron
sulfide
Halite- rock salt- sodium chloride
Sodium chloride is an ionic compound
with ions arranged in a lattice
Ions
charged particles with electrostatic attraction between them
Na+
Cl-
Common Cations
Common Name Formula Alternative
name
Simple Cations
Aluminium
Al3+
Calcium
Ca2+
Copper(II)
Cu2+
cupric
Hydrogen
H+
Iron(II)
Fe2+
ferrous
Iron(III)
Fe3+
ferric
Magnesium
Mg2+
Mercury(II)
Hg2+
mercuric
Potassium
K+
kalic
Silver
Ag+
Sodium
Na+
natric
Polyatomic Cations
Ammonium
NH4+
Hydronium
H3O+
Common Anions
Common Name Formula
Simple Anions
Chloride
Cl−
Fluoride
F−
Bromide
Br−
Oxide
O2−
Polyatomic anions
Carbonate
CO32Hydrogen
HCO3−
carbonate
Hydroxide
OH−
Nitrate
NO32Phosphate
PO43Sulfate
SO42Anions from Organic Acids
Ethanoate
CH3COO−
Methanoate
HCOO−
Ethandioate
C2O4−2
Cyanide
CN-
Alternative
name
bicarbonate
acetate
formate
oxalate
Electronic configuration
of noble gas atoms
Draw the electronic structure of the first
4 noble gas atoms
How do ions form?
Sodium and chloride ions formed when
electrons transfer
Na
2,8,1
+
Cl
2,8,7

Na+
2,8
+
Cl2,8,8
Lithium chloride
Magnesium chloride
Sodium oxide
How do lithium fluoride crystals form ?
5-8 sentences
anion
cation
electron transfer
stable electronic
configuration
full outer shell
electrostatic force
crystal lattice
Formulas for ionic
compunds
Ionic compounds
formed from an cation Fe3+ and a anion O2have a formula eg Fe2O3
(without charges)
name from cation and anion eg iron oxide
no charge overall
(charges shown)
Finding the formula of an ionic
compound
 add up charges on each ion, or
 drop and swap and simplify or
 algebra
What is the formula of iron (III) oxide?
Fe2O
FeO
Fe3O2
Fe2O3
Ions
 Group 1: H+, Li+, Na+, K+, Rb+, Cs+, Fr+
 Group 2: Be2+, Mg2+, Ca2+, Sr2+, Ba2+
 Group 13 (or 3): B3+, Al3+, Ga3+
 Group 16 (or 6): O2-, S2-,
 Group 17 (or 7): F-, Cl-, Br-, I-
Polyatomic ions
Polyatomic ions are ions made of more
than one atom with an overall charge
sulfate, SO42-
https://en.wikipedia.org/wiki/Sulfate
Calcium sulfate
calcium ion, Ca2+
sulfate ion, SO42calcium sulfate CaSO4
Image: https://en.wikipedia.org/wiki/Calcium_sulfate
Some common polyatomic ions
 Nitrate NO3 Hydroxide OH-
 Sulfate SO42 Carbonate CO32 Hydrogen carbonate HCO3-
(Bicarbonate)
 Phosphate PO43 Ammonium NH4+
(Also nitrite NO2-, sulfite SO32-, cyanide CN-, ethanoate CH3COO-)
Common anions and
cations
Careful with...
 name of atom can change when ion is formed
chlorine atom (Cl)  chloride ion (Cl-)
 -ate is often a polyatomic ion with oxygen eg sulphate,
phosphate, etc.
 different ions often have similar names...
 nitrate NO3 nitrite NO2-
 nitride N-3
What is the formula of ammonium
sulphate?
 NH4SO4
 (NH4)2SO4
 NH4(SO4)2
 SO4(NH4)2
d-block (transition elements) can have
variable valencies
Mn2+
manganese(II)
Cr2+
chromium(II)/chromous
Mn3+
manganese(III)
Cr3+
chromium(III)/chromic
Mn4+
manganese(IV)
Cu1+
copper(I)/cuprous
Ni2+
nickel(II)/nickelous
Cu2+
copper(II)/cupric
Ni3+
nickel(III)/nickelic
Fe2+
iron(II)/ferrous
Pb2+
lead(II)/plumbous
Fe3+
iron(III)/ferric
Pb4+
lead(IV)/plumbic
Hg2+
mercury(I)/mercurous
Find the formula of
 Lithium fluoride
 Aluminium oxide
Covalent bonding between
non-metal atoms
Using a text book
 Skim read the text
 Write one sentence to explain what it is about
 Read the text carefully
 Write 3-5 bullet points or diagrams
 Write at least 2 questions you still have about the concept
 Answer the questions at the end of the sheet
Covalent bonding makes molecules
Covalent bonding forms molecules
Often between non-metals
Covalent bond formation- valence electrons
2, 4 or 6 electrons?
 Single bond: the two atoms share two electrons (1 pair)
 Double bond: the two atoms share four electrons (2 pairs)
 Triple bond: the two atoms share six electrons (3 pairs)
Lewis structures (dot structures) show valence
electrons in pairs as dots, crosses or lines
skeletal formula for complex organic
molecules
Condensed formula
propanol CH3CH2CH2OH
Draw diagrams to show the atoms and
valence electrons in the compounds:
Fluoromethane, CH3F
Magnesium fluoride, MgF2
Properties of ionic and covalent
molecular compounds
Ionic compounds
Property
Crystalline
High melting and boiling
points
Soluble in polar solvents
(eg water)
Insoluble in non-polar
solvents (eg oil)
Conduct electricity when
dissolved in water
Explanation in terms of the arrangement
and bonding of atoms
Covalent molecular compounds
Property
Lower melting and boiling
points
Insoluble in polar solvents (eg
water)
Soluble in non-polar solvents
(eg oil)
Do not conduct electricity
Explanation in terms of the
arrangement and bonding of atoms
Covalent macromolecules
Diamond- an allotrope of carbon
Silicon dioxide, SiO2
Metallic bonding
Metallic bonding- positive ions
surrounded by delocalized electrons
Links
 Bonding
http://www.pbslearningmedia.org/resource/lsps07.sci.phys.m
atter.chembonds/chemical-bonds/
 Ionic bonding
http://www.pbslearningmedia.org/asset/lsps07_int_ionicbon
ding/
 Covalent bonding
http://www.pbslearningmedia.org/asset/lsps07_int_covalent
bond/