chemistry module form 4 (2)

mohd faisol mansor/chemistry form 4/chapter 2

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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


10

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

________________.



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

________________.



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

________________.



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


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


Silicon

14

Phosphorus

15

Sulphur

16

Chlorine

17

Argon

18


21

Element Proton

Number

Number of

Electron

Electron

Configuration &

Valence

Electron


Potassium

19

Calcium

20

chemistry module form 4 (2)

Documents

solid naphthalene

atom matter

type of atom

temperature of naphthalene

glass of water atom

solid liquid gas shape

solid changes

different particles