SUBJECT: PHYSICAL SCIENCE
GRADE: 10
CHAPTER / MODULE 4: MATTER AND MATERIALS
UNIT / LESSON TOPIC: MATERIALS – A MACROSCOPIC VIEW
LESSON:
1.
INTRODUCTION
It is very important to us to know more about the types of material (matter) that we use in everyday life and the reason why we use it.
Houses are build with specific types of material: Bricks, stones, polystyrene, zink. Each one of these materials has advantages and
disadvantages. Bricks are quite expensive but are an excellent insulator. Stones are difficult to get because is must be a specific shape, but is
also an excellent insulator. Polystyrene is a new method for building houses and are not readily available, it is also very expensive, but it is the
best insulator. Corrugated zinc is the cheapest material, easily available but it is a very poor insulator and one has to use lots of innovative ways
to insulate it to make living in it comfortable.
Clothes are made of specific materials for specific purposes. The clothes of a biker are made to protect the person while clothes that we wear in
summer are made to keep us cool.
Hats that we wear are also made for different purposes. A helmet and a sun hat are made from different types of material because it is used for
different purposes.
2.
CLASSIFYING OF MATTER
Matter
Mixtures
Pure substance
Heterogeneous
mixtures
Compounds
Elements
Metals
Semi metals
Homogeneous
mixtures
Non metals
Organic
Inorganic
A mixture is when two or more substances are mixed. The ratios in which the substances are mixed are irrelevant. There are no chemical bond
between the substances and it can be separated with physical methods like sifting, filtering a magnet etc.
A homogeneous mixture is when the substances are in the same phase. A heterogeneous mixture is when the substances in the mixture are in
different phases.
A pure substance is a single substance; it can be a single element or a single compound.
An element is the simplest type of pure substance. It can not be broken down in smaller of simpler types or substances.
A compound is a pure substance that consists of two or more elements that are chemically bonded.
3.
THE PERIODIC TABLE OF ELEMENTS.
The periodic law states that if elements are arranged according to its atomic number show periodic change in its properties.
The modern periodic table is organised in rows (periods) and columns (groups). There are 7 periods. There are 8 main groups; the elements are
arranged to have similar chemical and physical properties in the same group.
2
THE PERIODIC TABLE OF ELEMENTS
3
5
4
6
8
7
9
10
11
12
13
(III)
14
(IV)
15
(V)
16
(VI)
17
(VII)
Atomic number
58
Ce
140
90
Th
232
3
63
Eu
152
95
Am
64
Gd
157
96
Cm
65
Tb
159
97
Bk
66
Dy
163
98
Cf
67
Ho
165
99
Es
68
Er
167
100
Fm
69
Tm
169
101
Md
4,0
3,0
2,8
2,5
8
O
16
16
S
32
34
Se
79
52
Te
128
84
Po
2,5
3,5
2,5
2,4
2,1
7
N
14
15
P
31
33
As
75
51
Sb
122
83
Bi
209
2,0
3,0
2,1
2,0
1,9
6
C
12
14
Si
28
32
Ge
73
50
Sn
119
82
Pb
207
1,9
2,5
1,8
1,8
1,8
1,5
1,9
1,9
93
Np
62
Sm
150
94
Pu
1,6
1,8
2,2
61
Pm
30
Zn
65
48
Cd
112
80
Hg
201
1,7
1,8
2,2
60
Nd
144
92
U
238
1,6
1,8
2,2
59
Pr
141
91
Pa
29
Cu
63,5
47
Ag
108
79
Au
197
1,7
1,5
1,9
23
V
51
41
Nb
92
73
Ta
181
1,6
1,6
22
Ti
48
40
Zr
91
72
Hf
179
Approximate relative atomic mass
24
25
26
27
28
Cr
Mn
Fe
Co
Ni
52
55
56
59
59
42
43
44
45
46
Mo
Tc
Ru
Rh
Pd
96
101
103
106
74
75
76
77
78
W
Re
Os
Ir
Pt
184
186
190
192
195
1,8
1,4
1,6
21
Sc
45
39
Y
89
57
La
139
89
Ac
1,5
63,5
5
B
11
13
Aℓ
27
31
Ga
70
49
In
115
81
Tℓ
204
1,8
2,0
Symbol
Cu
1,8
29
1,9
Electronegativity
1,3
4
Be
9
12
Mg
24
20
Ca
40
38
Sr
88
56
Ba
137
88
Ra
226
1,2
1,0
1,0
1,2
1,5
KEY
0,9
1
H
1
3
Li
7
11
Na
23
19
K
39
37
Rb
86
55
Cs
133
87
Fr
2
(II)
0,9
0,7
0,7
0,8
0,8
0,9
1,0
2,1
1
(I)
9
F
19
17
Cℓ
35,5
35
Br
80
53
I
127
85
At
70
Yb
173
102
No
18
(VIII)
2
He
4
10
Ne
20
18
Ar
40
36
Kr
84
54
Xe
131
86
Rn
71
Lu
175
103
Lr
Chemical symbols are used to represent elements. The first letter of the symbol is always a capital letter and the second letter (if any) will be a
small letter. Two capital letters next to one another indicates a compound where two elements are chemically bonded.
4.






METALS, SEMI-METALS AND NON-METALS
Meals are good conductors of heat and electric current.
Metals are usually shiny
Metals are malleable (can be pounded into shape).
Metals are ductile (can be drawn into long threads).
Metals are solids at room temperature. Mercury is the only exception.
Metals have high melting and boiling points.





Non-metals are dull.
Non-metals are good insulators.
Non-metals do not conduct electricity or heat.
Many non-metals are gasses at room temperature.
Non-metals have low melting and boiling points.






Semi-metals have metal and non-metal properties.
Semi-metals are solids at room temperature.
Semi-metals are not malleable or ductile.
Semi-metals give greater resistance than metals to conduct electricity and heat at room temperature.
If semi-metals react with metals it acts as non-metals.
If semi-metals react with non-metals it acts as metals.
Metals are found on the left hand side of the Periodic Table. Non metals are found on the right side of the Periodic Table. The semi-metals are
found between the metals and the non-metals.
5.
CHEMICAL FORMULAE
When compounds form there is specific ways in which this compounds is named. It is important to be able to classify the elements in the
compound as metals and non-metals so that the rules can be applied.

When a metal bond to a non-metal:
4
Write the metal (which is more to the left o the periodic table) first followed by te non-metal.
Write the name of the metal, then the name of the non-metal followed by the suffix -ide.
NaCl: sodium chloride.
MgO: magnesium oxide

When a transition metal bond to a non-metal:
Write the name of the transition-metal (which is more to the left) first, then the charge of the transition metal (in roman numerals) and
lastly the name of the non-metal with the prefix –ide.
FeCl3: Iron (III) chloride
CuO: copper (II) oxide

When two non-metals bond to one another:
Write the name of the non-metal that is more to the left on te Periodic Table first, then the number of atoms for the second non-metal,
the name of the second non-metal and the prefix –ide.
CO2: Carbon di oxide
NO3: Nitrogen trioxide.
When elements combine, it always happen in fixed ratios. To know which ratio to use we have to look at the valence electrons and the valency
of each element.
The valence electrons are the number of electrons in the outer energy level of an atom. The number of valence electrons are equal to the
group number of the element.
For a metal the valency is equal to the group number.
For a non-metal the valency is equal to 8 – the group number.
When two elements combine we use the valencies to determine the ratio in which the elements will combine. The number ot atoms of an
element that is needed for the bond is indicated with a small number after the symbol of the element.
5
When potassium (K) bonds to oxygen (O) the following ratio occur:
Potassium (K) has a valency of 1, oxygen has a valency of 2.
The valencies will now cross to indicate the ratio:
K
1
+
O
2
K2O
When a group of non-metals bond together and a group form an ion it is called s radical or a poly-atomic ion.
Name of the radical
Symbol
Valency
+
Ammonium
NH4
1
Hydroxide
OH1
Nitrate
NO3
1
Bicarbonate
HCO3
1
Sulphate
SO422
2Carbonate
CO3
2
Phosphate
PO433
6.
MACRO – AND MICROSCOPIC PROPERTIES
When we refer say that salt is a solid and water at liquid at room temperature, we refer to the macroscopic properties of salt and water.
Macroscopic properties are properties such as temperature, pressure and volume. If you want to explain these properties we have to talk
about the particles and the forces between them. This is the microscopic forces.
Particles in a liquid move faster at a higher temperature, which is why a warmer liquid will evaporate faster than a cooler liquid. When the
particles move faster, it is possible for them to have enough speed to escape from the attraction forces exerted on them by the surrounding
particles.
6
The shape of a solid can not be changed because the particles have fixed positions. Because the particles vibrate in its fixed position, the
temperature of a solid can change. The solid will be become warmer when the particles vibrate faster in its fixed position. If the particles gain
enough speed it will break loose and the solid will melt into a liquid.
Gasses will spread faster when it is warmer because the particles will move faster at a higher temperature.
We can thus conclude that for all phases of matter (solid, liquid and gas), a higher temperature means that the particles move faster.
The kinetic theory of matter states that the matter is made up of tiny particles that move all the time.
 All matter is made up of tiny, invisible, moving particles. The particles can be atoms, molecules or ions.
 Whether matter is a solid, liquid or gas, the particles move all the time. The higher the temperature, the faster the particles will move.
Gas phase:
 The average distance between the particles is much greater than the distance in liquids or solids.
 Because of the big distances the force of attraction between the particles are very small.
 The molecules move all the time. Because they collide and change direction all the time we find a random motion.
 A gas will fill the whole container it is kept in.
 The average kinetic energy is directly proportional to the temperature of the gas.
Liquid phase
 The particles are quite close together, but the force of attraction is smaller than in a solid, but greater than in a gas.
 The particles have more freedom of movement than in a solid but less than in a gas.
 Liquids can flow past each other.
 The average kinetic energy is directly proportional to the temperature of the liquid.
Solid phase:
 The particles attract each other strongly with intermolecular forces.
 The particles are arranged in a fixed way.
 Particles can vibrate.
 The particles are arranged in a regular way and form beautiful crystals.
 The average kinetic energy is directly proportional to the temperature of the solid.
7
The density of a substance is the mass of 1cm3 of the substance. The density depends on the mass of the particles and how close the
particles are packed.
ACTIVITIES:
Activity 1:
Name the following compounds:
Na2S; HCl
Activity 2:
Give the formulae for the following compounds.
Magnesium chloride; Phosphorous tri fluoride.
Activity 3:
Explain the difference in the movement of the three phases of matter
PORTFOLIO EXERCISE:
1. Classify everything that you can get in the class as metals, non-metals, mixtures and pure substances.
REVIEW QUESTIONS
1.
Name the following compounds:
MgO
NaF
ZnBr2
CO
Al2O3
H2SO4
2.
Write the formula for the following compounds.
Hydrogen fluoride
8
Calcium sulpide
Iron (III) sulphate
Ammonium oxide
Calcium iodide
3.
Classify the following as mixtures or pure substances.
Pure orange juice; dairy milk chocolate, copper sulphate; honey
4.
Classify the following elements as metals and non-metals.
Iron, oxygen, sulphur, cobalt, phosphorus, lithium.
9