4. 2.1 Basic Concepts of Matter
2.1.1 Describe matter briefly
2.1.2 Explain the changes in the states
of matter
2.1.3 Determine the melting point and
freezing point of naphthalene
through activity
5. What is matter (with matter)?
Matter consist of particles that are tiny and
discrete
Ice cream melts because it absorbs heat
energy and changes from solid to liquid
state. Water vapour in the air that comes
in contact with cold surface loses heat and
forms water droplets on the surface.
Example
Meaning
Matter is something that has
mass and occupies space
State of matter
Matter can exist in three
states; solid, liquid and gas
Four states of matter
Plasma is an ionized gas.
Most stars exist as plasma
Changes in state of matter
The change of state of matter
is caused by heating & cooling
6. Conversion between states of matter
Melting
Boiling/
Evaporation
Sublimation
Deposition
Freezing
Condensation
Key:
Heat energy absorbed
Heat energy released
7. State of matter Solid Liquid Gas
Arrangement of
particles
Particles closely
packed in an
orderly manner
Particles closely
packed but not in
an orderly manner
Particles are far
apart
Kinetic energy Low
Higher than solid
state
Very high
Attraction force
between particles
Strong
Strong but less
than solid state
Weak
11. Melting Point and Freezing Point
Melting point is the constant temperature when
a substance changes from solid state to
become liquid at a specific temperature
Melting Point
Freezing point is a constant temperature when
a substance changes from liquid state to
become solid at a specific temperature
Freezing Point
17. Discussion
1. During the heating of naphthalene, C10H8:
(a) Why is naphthalene, C10H8 not heating directly using the Bunsen burner?
(b) Why is a water bath used?
(a) Naphthalene is a flammable substance
(b) Water bath method helps to distribute heat evenly. This ensures even
heating
18. 2. During the cooling of naphthalene, C10H8:
(a) Why is the boiling tube put into a conical flask?
(b) Why is a naphthalene, C10H8 stirred continously?
(c) Predict what would happen if naphthalene, C10H8 is not stirred continously
(a) To ensure even cooling
(b) To distribute heat evenly
(c) Supercooling will happen
3. Explain why the temperature becomes constant when melting and freezing
of naphthalene, C10H8 take place.
During melting, heat energy that is absorbed by the naphthalene particles
C10H8 is used to overcome attraction force between the particles so that the
solid changes to liquid.
During cooling, heat energy that is released to the surroundings is balanced by
the heat energy released when particles attract each other to form a solid.
19.
20.
21.
22. Test Yourself 2.1 (page 29)
1. State the types of particles that exist in a copper wire.
Atom
2. Lily dries her hair with a hair dryer
(a) Name the process involved during hair drying
(b) Sate the changes in the movement of water particles when hair is dried
(a) Evaporation
(b) Water molecules move more freely and faster
23. 3. Lauric acid, C12H24O2 is heated from room temperature to 50 oC. At 43 oC,
lauric acid, C12H24O2 starts to melt.
(a) Draw a heating curve for lauric acid, C12H24O2.
(b) Why is the temperature constant at 43 oC?
(b) Heat energy that is absorbed
by the lauric acid particles,
C12H24O2 is used to overcome
attraction force between the
particles until the solid
changes to liquid.
25. 2.1 Basic Concepts of Matter
2.2.1 State the subatomic particles in
atoms of various elements
2.2.2 Compare & contrast the relative
mass and relative charge of proton,
electron and neutron
2.2.3 Sequence the atomic structure
models based on Atomic Models of
Dalton, Thomson, Rutherford, Bohr
and Chadwick
30. John Dalton
• Matter is made up of
particles called atom
• An atom is the smallest
spherical body that
cannot be created,
destroyed nor divided
further
(1766 – 1844)
• Same elements have the
same atoms
31. J.J. Thomson
• Discover negatively-
charged particles called
electrons
• Atom is a positively-
charged sphere with
several electrons in it
(1856 – 1940)
32. Ernest Rutherford
• Nucleus is the centre of
the atom
• Discovered positively-
charged particles called
protons in the nucleus
(1871 - 1937)
• Electrons move outside
the nucleus
• Almost the whole of
atomic mass is
concentrated in the
nucleus
34. James Chadwick
• Discovered neutral
particles, that are
neutrons in the nucleus
• Neutrons contribute
almost half of the mass
of an atom
(1891 – 1974)
38. Test Yourself 2.2 (page 32)
1. Figure 2.10 shows the atomic structure of nitrogen.
(a) Name X.
(b) State the subatomic particles found in the nucleus of nitrogen atom
(c) Compare X and subatomic particles mentioned in (b) from the aspect of
relative charge and relative mass
(a) Electron
(b) Proton and neutron
Subatomic
particles
Electron Proton Neutron
Relative charge -1 +1 Neutral
Relative mass 0 1 1
39. 2.
• Electrons move around the nucleus in shells
• Nucleus of an atom consists of protons and neutrons
The statement above show the information on an atomic structure model.
(a) Which scientist identified it?
(b) Draw this atomic structure model
(a) James Chadwick
41. 2.3 Atomic Structure
2.3.1 Define proton number and
nucleon number
2.3.2 Determine the nucleon number,
proton number and number of
electrons in an atom
2.3.3 Write the standard representation
of an atom
2.3.4 Construct an atomic structure
diagram and electron arrangement
43. An atom is neutral when the number of electrons is the same with the
number of protons. For example, an oxygen atom has 8 protons and also 8
electrons.
44.
45. Type of particle Sodium atom, Na Sodium ion, Na+
Number of proton 11 11
Number of neutron 12 12
Number of electron 11 10
46. Standard Representation of an Atom
The symbol of carbon element is C
The nucleon number of a carbon atom is 12
The proton number of a carbon atom is 6
52. Proton number of aluminium is 13
An aluminium atom has 13 electrons
The electron arrangement of aluminium atom is 2.8.3
Number of valence electrons of aluminium atom is 3
53. Activity 2.6 & 2.7
Page 36 Form 4 KSSM Chemistry Text Book
54.
55.
56.
57. Test Yourself 2.3 (page 36)
Table 2.3 shows the number of protons and the number of neutrons for
elements X, Y and Z.
1. What is the nucleon number of atom Y?
23
2. Write is the standard representation of element Z.
3. Atom Y donates one electron to form ion Y+. State the number of protons,
neutrons and electrons for ion Y+
Number of proton = 11, number of neutrons = 12, number of electrons = 10
58. Test Yourself 2.3 (page 36)
4. (a) Write the electron arrangement of atom X.
2.8
(b) Draw the electron arrangement
for atom X
(c) Draw the atomic structure of atom X. Label
all the subatomic particles in the diagram
60. 2.4 Isotopes and Its Uses
2.4.1 Deduce the meaning of isotopes
2.4.2 Calculate the relative atomic mass
of isotopes
2.4.3 Justify the usage of isotopes in
various field
61. Meaning of Isotopes
Isotopes are atoms of the same element with the
same number of protons but different number of
neutrons.
66. Uses of Isotopes
Hydrogen-3 : As a detector to study sewage and liquid wastes
Industry
Cobalt- 60 : In radiotherapy to kill cancer without surgery
: Sterilising surgical tools
Iodine-131 : Treatment of thyroid disorders such as
hyperthyroidism and thyroid cancer
Medicine
Phosphorus-32 : Study plant metabolism
Agriculture
Uranium-235 : Generating electricity through nuclear
power generator
Nuclear
Carbon-14 : Estimation of artifacts or fossils’ age
Lead-210 : In determining the age of sand and earth
layers up to 80 years
Archeology
Sodium-24 : In detecting leaking in underground pipes
Engineering
67. Medicine
Cobalt- 60 : In radiotherapy to kill cancer
without surgery
Cobalt- 60 : Sterilising surgical tools
76. Test Yourself 2.4 (page 39)
1. Define isotopes.
Isotopes are atoms of the same element with the same proton number / same
number of protons but with different nucleon number / number of neutrons.
2. Based on Table 2.6, which atoms are isotopes? Explain your answer.
Atoms W and X
This is because the atom W and X have the same
number of protons / same number of protons but
different nucleon number / number of neutrons.
77. 3. Atoms of oxygen-16, oxygen-17 and oxygen-18 are isotopes. Compare and
contrast these three isotopes.
Similarity:
• This atom is from the same element, that is oxygen
• The number of protons in the nucleus of this atom is the same
• The chemical properties of these atoms are the same
Differences:
• The nucleon number of all three atoms is different. The nucleon number for
oxygen-16 is 16, the nucleon number for oxygen-17 is 17 and the nucleon
number for oxygen-18 is 18.
• The number of neutrons in the nucleus of all three atoms is different. Oxygen-
16 has 8 neutrons, oxygen-17 has 9 neutrons and oxygen-18 has 10 neutrons.
• The physical properties of all three atoms are different.
78. 4. Magnesium exists naturally as three isotopes, which are 79.0% of 24Mg,
10.0% 25Mg and 11.0% 26Mg. Calculate the relative atomic mass of
magnesium.
Relative atomic mass of magnesium
5. Madam Maimunah was diagnosed with bone cancer.
(a) What isotope is used to treat Madam Maimunah?
(b) Explain the positive and negative effects of using the isotope in (a).
