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2.1 Matter 

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Matter 

Anything that occupies space and has mass

Matter 

Element Compound

Atom Molecule Molecule Ion

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Particulate nature of matter 

Tiny and discrete

Diffusion proves that matter is made

up of tiny particles.

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Kinetic theory of matter 

Matter consists of tiny, discrete particles

that are constantly moving.

The particles move in a random motion 

and collide with one another .

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Diffusion

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Change of state

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Heating graphCompletely melted

Completely vaporised

Even heating

Melting point > 100°C?

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Cooling Graph

Even cooling

Energy lost = heat energy released

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Comparison

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2.2 Atomic structure

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2.2 Atomic structure

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Subatomic Structure

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Atomic Structure

Proton number 

= number of protons

Nucleon number = no. of neutrons + no.

of proton

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Symbol of Elements

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2.3 Isotopes

The Isotopes of an element are the atoms

of that element which contain the same

number of protons but a different number 

of neutrons.

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The Uses of Isotopes

Medical (a) Cobalt-60 are used in radiotherapy

(b) Iodine-131 can be injected into the thyroid gland of 

patient with hyperthyroidism (over-active thyroid gland) todestroy the hyperactive thyroid cells.

(c) Sodium-24 is injected into the body to identify thelocation of a blood clot.

(d) Carbon-14 are used in determine the age of fossil.

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2.4 The Electronic Structure of an

Atom

1 The electron configuration (electron

arrangement) of an atom is the

arrangement of electrons in shells (orbits)

around that atom's nucleus.

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2.4 The Electronic Structure of an

Atom

2 The electrons in an atom are arranged

in shells around the nucleus. The

maximum number of electrons which can

fill a particular shell is as follows:

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2.4 The Electronic Structure of an

Atom

3 The electrons in the last shell of an

atom are known as valence electrons.

They determine the chemical properties of 

the element.

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2.4 The Electronic Structure of an

Atom

4. Sulphur has 16 electrons:

The electronic configuration or electron

arrangement is then written as 2.8.6.

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2.4 The Electronic Structure of an

Atom

5 All elements having the same valence

electrons will show the same chemical

properties, for example, chlorine and

bromine, have 7 valence electrons, willexhibit similar chemical properties.

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2.4 The Electronic Structure of an

Atom

6 Helium has a complete shell of 2 valence

electrons or duplet condition. Similarly, neon

and argon also have complete shells. They have

8 valence electrons or the octet condition.These elements are monoatomic and are very

stable gases.

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2.4 The Electronic Structure of an

Atom

7 The electron arrangement of an

element, for example;Na is constructed by

drawing 3 circles around the nucleus to

represent each shell, as its electronconfiguration is 2.8.1. Thus we have

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2.4 The Electronic Structure of an

Atom

8 Table 2.5 shows the electron arrangement of 

the first 20 elements in the Periodic Table.

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2.4 The Electronic Structure of an

Atom