TOPIC 1
MATTER AND THE THEORY OF STATE MATTER
INTRODUCTION
TO THE
MATTER
 Matter is anything that occupies space and has mass.
 Matter can classified into physical and chemical state.
 There are 4 physical states of matter :
1) Gas or Vapor
 No fixed volume or shape - it conforms to the container.
 Can be compressed or expanded
 Move randomly at great speeds
 Can vibrate, rotate, translate & have highest energy
content
2) Liquid
 Has a fixed volume - shape depends on its container.
 Cannot compressed.
 Particle can vibrate, rotate & translate.
3) Solid
• Has a fixed shape and volume; it is rigid
• Cannot compressed.
• Particles can vibrate & rotate at fixed positions
4) Plasma
 is a substance similar to gas in which electrically
neutral medium of positive and negative particles
 they generate electrical currents by charges.
THEORY OF STATE MATTER
 Matter is made up of tiny and discrete particles. There are
spaces between these particles.
 The particles may be atoms, molecules or ions.
 An atom is the smallest particle of an element that can
participate in a chemical reaction.
 A molecules is a group of two or more atoms which are
chemically bonded together.
 An ion is a positively-charged or negatively-charged
particle.
 Particles of Matter are constantly moving & contain
kinetic energy.
 Particles of Matter are held together by very strong
electric forces
 Matter can be classified by its chemical constituent
whch are elements and compounds.
a) An elements is a substance that consists of only
one type of atom.
b) A compound is a substance that contains two
or more elements that are chemically bonded
together.
5. Each substance has unique particles that are different
from the particles of other substances
6. Temperature affects the speed of the particles. The
higher the temperature, the faster the speed of the
particles.
MATTER
ELEMENT
COMPOUND
ATOM
MOLECULES
MOLECULE
S
e.g: Gold, Au
e.g: Oxygen gas,
O2
e.g: Water,
H2O
Argon gas, Ar
Sulphur, S8
Carbon
Dioxide gas,
CO2
ION
e.g: Sodium
chloride,
NaCl
Matter
Anything with mass and volume
Substance
Matter with constant composition
Mixture
Matter with variable composition
Element
Substance made up
of only one type of
atom
Compound
Two or more
elements that are
chemically
combined
Heterogeneous
Mixture
Mixtures that are
made up of more
than one phase
Homogeneous
Mixtures
Also called
solutions. Mixtures
that are made up of
only one phase
Examples - gold,
silver, carbon,
oxygen and
hydrogen
Examples - water,
carbon dioxide,
sodium
bicarbonate,
carbon monoxide
Examples - sand,
soil, chicken soup,
pizza, chocolate
chip cookies.
Examples - salt
water, pure air,
metal alloys, seltzer
water.
Solid
Liquid
Gas
Attractive force
among particles
Strong
Fairly strong
Very weak
Compressibility
Incompressible
Incompressible
Easy to compress
Volume
Fixed
Particle movement
Can only vibrate
Free to move slowly
Free to move
quickly
Shape
Definite
No definite shape
(Fill bottom of the
container)
No definite shape
(Fill the whole
container)
Kinetic energy
Low
Medium
High
Particles
arrangement
Fixed and similar to
No fixed volume
solid
(occupies the whole
container)
Sublimation
Boiling/
Melting
evaporation
Freezing Condensation
LIQUID
SOLID
GAS
Sublimation
Heat energy absorbed
Heat energy released
Melting point –
Temperature at which
During Heating…
 When a solid is heated, the particles absorb heat
energy.
 The particles vibrate faster and kinetic energy
increase.
 The movement of particles is increase
 The force of attraction become weak
Freezing point –
Temperature at which
During Cooling…
 When a gas is cooled, the particles release the
energy.
 The kinetic energy will decrease
 The movement of particles is decrease
 The force of attraction become strong
PHYSICAL AND CHEMICAL
CHANGES
PHYSICAL CHANGES
CHEMICAL CHANGES
 A change that alters the
 a change in matter that
APPEARANCE of a material
but does not make the
material into another
substance
 Physical changes are
REVERSIBLE
 Examples: tearing paper,
chopping wood, molding
clay, melting ice
PRODUCES A NEW
SUBSTANCE
 Signs that a chemical change
has taken place:






bubbles appear
precipitate forms
color change
light is emitted
temperature change
change in smell or taste
S involved during BOTH physical and c
Subatomic particles of an atom
 Atoms are made up of three types of smaller particles,
namely protons, neutrons and electrons. These
particles are known as subatomic particles.
 The relative masses and charges of these three
subatomic particles in table below.
SUBATOMIC
PARTICLE
SYMBOL
RELATIVE MASS
RELATIVE
ELECTRIC
CHARGE
PROTON
P
1
+1
NEUTRON
n
1
0
ELECTRON
e
0 (almost)
-1
Subatomic particles of an atom
 Protons and neutrons are found in the nucleus of an
atom while electrons surround the nucleus.
SYMBOLS OF ELEMENTS
 Each element is given a name and a symbol. Some
examples of elements and their symbols are shown
below.
ELEMENT
SYMBOL
ELEMENT
SYMBOL
Hydrogen
H
Sodium
Na
Helium
He
Magnesium
Mg
Lithium
Li
Aluminium
Al
Beryllium
Be
Silicon
Si
Boron
B
Phosphorus
P
Carbon
C
Sulphur
S
Nitrogen
N
Chlorine
Cl
 Notice that:
(a) Each symbols consists of one or two letters.
(b) For most elements, the letters used in their symbols
take either the first letter or first and another letter
of their names. Eg. Hydrogen, H; neon, Ne and
Magnesium, Mg.
(c) For some elements, the symbols come from Latin
names such as natrium (Na) for sodium and kalium
(K) for potassium.
11
5
Nucleon number
A
Z
Proton number
x
Symbol of
element
B
Proton number = 5
Nucleon number = 11
Neutron number = 11 – 5
=6
PROTON NUMBER & NUCLEON NUMBER
 Proton number : an elements is the number of protons in
its atom.
 Since atoms are neutral, the proton number is also the
number of electrons in the atom.
 Each elements has its own proton number.
 E.g:
 sodium has a proton number of 11. Hence all atoms of
sodium have 11 protons.
 Oxygen has a proton number of 8, so all oxygen atoms have
8 protons.
 The nucleon number is also known as the mass
number.
 The relative mass of an atom is almost the same as its
nucleon number. The nucleon number is sometimes
used as the approximate relative mass in calculations.
 Protons and neutrons are collectively called nucleons
because protons and neutrons occupy the nucleus.
 Nucleon number: total number of protons and total
number of neutrons in its atom.
 From definition,
Nucleon number = number of proton + number of neutrons
or
Number of neutrons = nucleon number – number of proton
 Remember the charge on each subatomic particle like
this:
Protons are positive,
Neutrons are neutral,
so electrons must be negative.
 In a neutral atom,
number of electrons = number of protons
ISOTOPES
 Isotopes are atoms of the same element
with the same number of protons but
different numbers of neutrons.
 Isotopes of an element have the same:
(a) number of protons in an atom.
(b) number of electrons in an atom.
(c) electron arrangement.
(d) chemical properties because they have the same
electron arrangement.
 Isotopes of an element have different:
(a) nucleon number.
(b) number of neutrons in an atom.
(c) physical properties (such as density, melting point
and boiling point), though these different are very
small.
USES OF ISOTOPES
 There are 2 types of isotopes, namely the radioactive
and the non-radioactive isotopes.
 Radioactive isotopes or radioisotopes produce harmful
radiation.
 However, radioisotopes can have important uses if
they are handled properly. They are used in medicine,
industry, agriculture and general research.
1) Medical use
 Gamma-rays emitted from cobalt-60 are used in
radiotherapy for the treatment of cancer.
 Superficial cancers such as skin cancer can be treated by
less penetrating radiation from phosphorus-32 or
strontium-90.
 A heart pacemaker which contains plutonium-238 is
used to regulate the heartbeats of patients with heart
problems.
 Iodine-131 is used in the treatment of thyroid diseases.
2) Agricultural uses
 The uptake of phosphate and the metabolism of
phosphorus by plants can be studied using a
phosphate fertiliser containing phosphorus-32.
 Radioactive tracer studies using carbon-14 have helped
in the understanding of photosynthesis and protein
synthesis.
3) Industry uses
 Sodium-24 can be used to trace leaks in gas or oil pipes
and ventilating systems.
 The gamma rays of cobalt-60 are passed through food to
destroy bacteria which cause the food to spoil without
changing the quality, flavour, or texture of the food.
 The radiation from krypton-85 can be used to control
the thickness of plastic sheets in the industry.
4) Power sources
 Uranium-235 is the most common fuel used in nuclear
power stations.
5) Archaeological uses
• Carbon-14 can be used to estimate the age
bone, wood or fossils by measuring the
fraction of carbon-14 it contains.
ELECTRONIC STRUCTURE OF AN ATOM
 Electrons are arranged around the nucleus in the shells
of an atom.
 The shell of an atom are numbered 1, 2, 3 and so on,
starting from the one closest to the nucleus.
 Each shell can occupy a certain number of electron.
ELECTRONIC STRUCTURE OF AN ATOM
First shell : 2 electrons
Second shell: 8 electrons
Third shell: 8 electrons
+
1
2
3
Fourth shell: 18 electrons
nucleus
FINDING THE ELECTRON ARRANGEMENT
 To write the electron arrangement of an atom, follow
these steps:
STEPS 1 – Find out the proton number of the atom. (can
refer to the Periodic Table)
STEPS 2 – Find out the number of electrons of the atom.
For a neutral atom, the number of electrons is the
same as the number of protons.
FINDING THE ELECTRON ARRANGEMENT
 STEPS 3 – Arrange the electrons in shells. Electrons
occupy the shell closest to the nucleus first. The
electrons only start occupying a new shell when the
previous one has been occupied.
VALENCE ELECTRONS
 Valence electrons are found in the outermost occupied
shell of an atom.
 They determine the chemical properties of the
element
VALENCE
ELECTRONS
 For e.g:
the electron arrangement of a chlorine atom is 2.8.7.
There are 7 electrons in the outermost occupied shell
of the chlorine atom. Therefore, the number of valence
electrons in a chlorine atom is 7.
1) How many states of matter are there?
A) 1 B)2 C) 3 D)4
ANS: There are 4 states of matter. You will find solids,
liquids, gases and plasmas.
2) Atoms in a liquid are farther apart than the atoms in a gas.
A) true
B) false
ANS: Atoms in a gas are actually farther apart than the
atoms in a liquid. Solids are the densest state of matter (of
solids liquids, and gases). Gases are the least dense and
have atoms that are the most spread out.
3) Which has the least energetic molecules?
a) Solids b) Liquids c) Gases d) Plasmas
Ans : Solids have the least energetic molecules. Plasmas
and gases have the most energetic atoms.
4) What force pulls liquids towards the ground?
a) Pressure b) Temperature c) Gravity
d) centrifugal
Ans: Gravity is the one force that pulls every object
towards the surface of the Earth.
5) When a substance goes from being a solid to a liquid,
it is a...
a) chemical change
b) Physical change
Ans: When a substance moves from one state to another,
it is a physical change. Physical changes usually
happen because you add or take away energy. If one
substance combines with another to make a new
compound... That is a chemical change.