CHAPTER 2 · PDF filemohd faisol mansor/chemistry form 4/chapter 2 5 CHAPTER 2 THE STRUCTURE...
Transcript of CHAPTER 2 · PDF filemohd faisol mansor/chemistry form 4/chapter 2 5 CHAPTER 2 THE STRUCTURE...
mohd faisol mansor/chemistry form 4/chapter 2
5
CHAPTER 2 THE STRUCTURE OF THE ATOM
Matter
Anything that occupies space & has
mass.
Type of Particles
Atom Molecule
Ion
Atom
Smallest particle of an element that can
take place in chemical reaction.
Ion
Is a positive charged or negative charged
particle.
Element
Substance that consists of only one
type of atom.
Compound
Substance that contains two or more elements
that are chemically bonded together.
Physical State
Solid Liquid Gas
Subatomic Particles
Electron Proton
Neutron
Diffusion Is a random movement
between different particles from high
concentration to lower concentration.
Molecule
A group of two or more atoms which are
chemically bonded together.
Matter is made up of tiny & discrete particle.
Particle vibrate, moving & collide with each other.
Particles move randomly. There are forces between
the particle. Stronger the forces, particle close to each other.
Higher the temperature, higher the kinetic energy of particle.
Kinetic Theory of Matter
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Example: Formation of WATER
Atom
+ Atom
Molecule (ELEMENT)
Atom
+ Atom
Molecule (COMPOUND)
Cation
+ Anion
Ionic Compound + + - -
+
Oxygen Atom
Hydrogen Atom
Water Molecule
A Glass of Water
Atom, Molecule & Ion
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Diffusion in Solid: Test tube is filled with a hot jelly and copper(II) sulphate crystal.
Diffusion in Liquid: A beaker is filled with water & potassium manganate (VII).
Diffusion in Gas: A gas jar is filled with few drop of bromine liquid.
Difussion Rate:
Reason:
Difussion Rate:
Reason:
Difussion Rate:
Reason:
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States Particles
Arrangement
Forces between
particles Particles Motion
SOLID
Packed closely in
orderly manner
Held together
very strong
Vibrate and rotate at
fixed position
LIQUID
Packed closely not in
orderly arrangement
Strong but weaker
than solid
Vibrate, rotate and
move through liquid &
collide against each
other
GAS
Far apart from each
other
weak Vibrate, rotate and
move freely
Solid
Liquid
Gas
Shape :
Ability to be
compressed:
Shape :
Ability to be
compressed:
Shape :
Ability to be
compressed:
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Change in the State of Matter
Changes in the Heat Energy
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Heating of Naphthalene Cooling of Naphthalene
1. Why is solid naphthalene, C10H8 not heated directly with Bunsen burner?
2. Why is water bath used to heat the naphthalene?
3. During the cooling of naphthalene, explain why
a) the boiling tube must place in a conical flask?
b) the naphthalene must stirred continuously?
4. What happens to the temperature of naphthalene during
a) melting? Give a reason.
b) freezing? Give a reason.
5. The melting point of sugar is 184oC. The melting point of sugar cannot be
determined using same apparatus. Why? What apparatus can be used
instead?
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The Heating Curve of Naphthalene
* label the melting point of the naphthalene in the diagram above as MP.
Melting Point
Is the temperature at which a solid changes into
a liquid at a particular pressure.
Physical State
AB =
BC =
CD =
Temperature (oC)
Time (min)
A
B C
D
Why the temperature increase from A to B?
When solid is heated,
heat energy is
________________.
This cause particles to
_________ kinetic energy
and vibrate __________.
Why the temperature remains constant at BC?
Heat energy ___________
by the particles is used to
overcome the force
between the particles so
that the solid turn into
liquid.
Why the temperature increase from C to D?
When liquid is heated,
heat energy is
________________.
This cause particles to
_________ kinetic energy
and move __________.
Also known as
latent heat of
fusion.
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The Cooling Curve of Naphthalene
* label the freezing point of the naphthalene in the diagram above as FP.
Freezing Point
Is the temperature at which a liquid changes
into a solid at a particular pressure.
Physical State
EF =
FG =
GH =
Why the temperature decrease from E to F?
When liquid is cooled,
heat energy is
________________.
This cause particles to
_________ kinetic energy
and move __________.
Why the temperature remains constant at FG?
Heat energy ___________
to the surroundings is
exactly same as the heat
energy released by
particle to form the
forces to become a solid.
Why the temperature decrease from G to H?
When solid is cooled,
heat energy is
________________.
This cause particles to
_________ kinetic energy
and vibrate __________.
Temperature (oC)
Time (min)
E
F G
H
How to avoid supercooling?
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The Atomic Structure
[Draw the atomic model & briefly explain]
(1) John Dalton
(1766 – 1844)
(2) J.J. Thomson
(1856 – 1940)
(3) Ernest Rutherford
(1871 - 1937)
(4) Neils Bohr
(1885 - 1962)
(5) James Chadwick
(1891 - 1974)
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Subatomic Particles of an Atom
PROTON
Symbol : p
Relative electric
charge : +1
Relative mass: 1
NEUTRON
Symbol : n
Relative electric
charge : 0
Relative mass: 1
ELECTRON
Symbol : e
Relative electric
charge : -1
Relative mass: 0.0005
NUCLEUS
Proton + Neutron
NUCLEON NUMBER =
Proton + Number of
Number Neutron
NEUTRAL ATOM
Number of proton
is equal to the
number of electron.
Definition
Nucleon number is
the total number of
proton and neutrons
in its atom.
Definition
Proton number is the
number of protons in
its atom.
Atom Q has a proton number
of 11 and a nucleon number of
23. How many protons,
electrons and neutrons are
present in the atom?
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Symbol of Elements
Element Symbol Element Symbol Element Symbol Element Symbol
Hydrogen
Carbon
Sodium
Sulphur
Helium
Nitrogen
Magnesium
Chlorine
Lithium
Oxygen
Aluminium
Argon
Beryllium Fluorine Silicon Potassium
Boron
Neon
Phosphorus
Calcium
Na
23
11
Also represented
by sodium-23
A fluorine atom has 9 protons and
10 neutrons. What is the proton
number and nucleon number of
the atom? Represent the atom in
the form of .
Bromine-80 has 45 neutrons.
What are the proton number
and nucleon number of the
atom? Represent the atom
in the form of .
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ISOTOPES
Atoms of the same element has same proton number but
different number of neutron
Element Nucleon
Number
Proton
Number
No. of
Neutron
No. of
Electron
Hydrogen-1 1
Hydrogen-2
Hydrogen-3
Carbon-12 6
Carbon-13
Carbon-14
Oxygen-16 8
Oxygen-17
Oxygen-18
Chlorine-35 17
Chlorine-37
Bromine-80 35
Bromine-81
USES OF ISOTOPES
To treat
cancer.
To determine
the age of
artifact.
To detect leaks in
underground
petroleum pipe.
To detect the
location of a
tumor in the brain.
To determine the
rate of absorption
of fertilisers by
plants.
Why isotopes element has similar chemical
properties?
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The Electronic Structure of an Atom
The last shell filled
with electrons
known as the
outermost
occupied shell.
Maximum number
of electron filled in
the shell:
1st = 2 electrons
2nd = 8 electrons
3rd = 8 electrons
4th = 8 electrons
For atoms with
more than 20
electrons, the third
shell can filled up
to 18 electrons.
Valence Electrons
Electrons in the
outermost
occupied shell.
Electron
Configuration
Chlorine has
proton number 17.
Write the electron
arrangement for
potassium & state the
valence electrons.
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Element Proton
Number
Number of
Electron
Electron
Configuration
& Valence
Electron
Electronic Structure
Hydrogen
1
E.C =
V.E =
Helium
2
Lithium
3
Beryllium
4
Boron
5
Carbon
6
Nitrogen
7
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Element Proton
Number
Number of
Electron
Electron
Configuration
& Valence
Electron
Electronic Structure
Oxygen
8
Fluorine
9
Neon
10
Sodium
11
Magnesium
12
Aluminium
13
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Element Proton
Number
Number of
Electron
Electron
Configuration &
Valence
Electron
Electronic Structure
Silicon
14
Phosphorus
15
Sulphur
16
Chlorine
17
Argon
18