Chemistry 20: Module 1: Lesson 3
1
Assignment
MODULE 1: LESSON 3 ASSIGNMENT
This Module 1: Lesson 3 Assignment is worth 50 marks. The value of each assignment
and each question is stated in the left margin.
(29+9=38/50
Marks)
Lesson 3 Assignment: Ionic Compounds
(16+8=24/30
marks)
1.
Fill in the table with the required information. The first one is done for you.
Atoms
Combined
Formula of Ions
Involved
Chemical
Formula
Name of
Compound
Na and Cl
Na+ and Cl–
NaCl
sodium chloride
Ca and Cl
K and Br
CaCl2
You need the
Ca2+ AND Clcorrect charges first
What is the
before you can
common ion charge
criss
cross them
of Ca? Look on the
and
write the
periodic table
formula
calcium chloride
K+ and Br-
KBr KBr
potassium bromide
Fe3+ and (OH)–
Fe2(OH)3
You need to keep
the polyatomic ion
in the brackets and
then criss cross the
charges
iron (III) hydroxide
Al and S
Al3+ and S2Use the periodic
table to check the
charges
Al2S3
You need the
correct charges first
before you can
criss cross them
and write the
formula
aluminium sulfide
Ni and CN
Ni3+and (CN)What is the charge
of Ni? And the
charge of CN? It is
in the polyatomic
ion chart
Ni(CN)3
nickel(II) cyanide
Ga2(SO4)3 •
18H2O
GALLIUM(III)
SULFATE
OCTADECAHYDRATE
FE AND OH-
Ga3+(SO4)2- and
H2O
GA(SO) and H2O
What is the charge
of Ga? And the
charge of SO4? It is
in the polyatomic
ion chart
Chemistry 20: Module 1: Lesson 3
2
Assignment
Cu2+AND N3Use the periodic
table to check the
charges
Cu3N2
copper (II) nitride
Mg2+ and O2–
MgO
Yes but you can
divide both charges
by 2 (lowest
common number)
and then you get
Mg1O1 or MgO
magnesium oxide
Al and O
Al3+ AND O2Use the periodic
table to check the
charge of Al
Al2O3
You need the
correct charges first
before you can
criss cross them
and write the
formula
aluminium (II) oxide
Not 2 (II)
Au+ AND BO
Au2+ AND BO3
What is the charge
of Au? And the
charge of BO3? It is
in the polyatomic
ion chart
Au3BO2
gold (II) borate
Cu AND N
MG+ AMD O-
Fe3+ and OH1OH is a poly atomic ion, it needs brackets
Fe3+ and (OH)1now criss cross the charges
Fe1(OH)3
FeOH3 = 1 Fe, 1 O, 3 Hs
Fe(OH)3 = 1Fe, 3Os, 3Hs
Ionic hydrates are on page 3 of your lesson, pg 31 in the textbook
(19+2/30=13+1/20
marks)
2.
Complete the following table.
Element
Electronegativity
Group
Number
Number
of
Valence
Electrons
Number
of
Bonding
Electrons
Number
of Lone
Pairs of
Electrons
Mg
1.3
2
2
2
0
Cl
3.2
17
7
1
6
Chemistry 20: Module 1: Lesson 3
3
Assignment
Al
1.6
13
3
3
0
Na
0.9
1
1
1
10
Si
1.9
14
4
4
4
H
2.2
1
1
1
0
P
2.2
15
5
3
1
Bonding electrons and Lone pairs - see page 91 Figure 2
Let’s do the first one together
Given 2 valence electrons, so that means it’s in group #2 (alkaline earth
metals), with 2 bonding electrons – no lone pairs, look up 1.3 on the periodic
table of group 2 and you will find Mg has 1.3
Once you have completed all of the questions, submit your work to your teacher.