Chapter 2 the structure of the atom

CHAPTER 2CHAPTER 2

2.1 MATTER Most of the things that we could see in this world are MATTER

What is matter?Matter means: - anything that occupies space & has mass

- made up of tiny & discrete particles

- Exist as element @ compound Next

A pure substance which cannot be broken down into simpler substance physically & chemically

Matter

Usually made up of two or more elements which are chemically

bonded together

Matter

1.Matter are made up of tiny & discrete particles

2. Size of particles are very minute ~~ 1x 10-7cm

3. Consist of atoms, molecules ions

Next

Let’s see the particles in bromine liquid

Particle theory

The smallest particle of an element and not breakable anymore.

Examples:

Atom of hydrogen

atom of magnesium

atom of oxygen

atom of chlorine

H

Mg

Cl

O

Particle theory

A group of two @ more atoms, which might consist of: one type of element (Element)

@ different types of element (Compound)

Examples of element molecules:

Molecule of hydrogen gas

Molecule of oxygen gas

Molecule of chlorine gasOO

Cl Cl

HH

Examples of compound molecules:

Molecule of water, H2O

Molecule of ammonia, NH3

Molecule of ethanol, C2H5OH

HH

O

H

H

H NO

C CH

H

H

HH

HParticle theory

Ions are atoms which have charge

Positively-charged ion /cation (loss

e-)

Negatively charged ion / anion (gain

e-)

+

-

Hydrogen atom

Hydrogen ion

Magnesium atom Magnesium

ion

Oxygen atom Oxide ion

Chlorine atom Chlorine

ion

Particle theory

H+

HLose electron

Mg2

+

Lose electronMg

O2

-

Gain electronO

Cl-

Gain electronCl

Symbol of element

Examples of ions:

• Kinetic means motion (move)• Kinetic theory states that:

1. Matter consist of particles which constantly moving

2. particles move in random motion , collide with each other

A. substance is cooled, - particles lose kinetic energy - move slower

B. substance is heated, - particles gain kinetic

energy- move faster

Heat energy makes particles move faster!!!

Experiment which supports the kinetic

theory:Investigating the diffusion of

particles in a solid, liquid and gas

What is diffusion ?What is diffusion ?

How diffusion supports How diffusion supports the the kinetic theorykinetic theory ? ?

Diffusion happens anyway that different concentration

of particles

Is the rate of diffusion different in solid, liquid,

and gas state?

Let’s get an experiment to check it out!!!

Diffusion in Solid (membrane)

Diffusion in Liquid ( )

Diffusion in Gas (air)

Diffusion affected by Density

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The conclusion is…….

• Diffusion happens in solid, liquid, and gas states

• Diffusion occurs slowest in solid, faster in liquid and fastest in gas

• Diffusion occurs faster in subtance with lower density

• Diffusion supports kinetic energy

The Physical States of Matter

Solid

Liquid

Gas

The Arrangement of Particles

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The Shape & Volume of Particles

The Movement & Energy Content of Particles

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The Attraction Force between Particles

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The Physical Changes of Matter

Freezing

GasLiquid

Solid

MeltingSublimatio

n

Boiling

Condensation

Sublimation

Determine the Melting Point of Naphthalene

Melting point – the temperature

which a solid becomes liquid

Diagram of heating naphthalene

Q1-Q4 Q5-Q7

Solid naphthalene

Water

Heating curve of naphthalene

A

CB

D

Temperature / ˚C

Time / minute

79˚C

Q1-Q4 Q5-Q7

What is the Melting point?A: 79˚C

What is the physical state at B-C?A: solid and liquid

Where is point that Melting process started?A: B

Where is point that Melting process ended?A: C

graph apparatus

Why the curve of heating has no change at B-C?A: because the heat energy absorbed by naphthalene molecules to overcome the forces of attraction to becomes liquid

Why solid naphthalene heated in water ?A: to ensure a uniform heating

If the melting point of Substance X is 123˚C, can we still use water as medium? Why?A: No. Because its melting point is higher than the boiling point of water. We can use oil bath to replace water. graph apparatusPhysical changes

Determine the Freezing Point of Naphthalene

Freezing point – the temperature which a solution

becomes solid

Cooling curve of naphthalene

Q1-Q4 Q5-Q7

79˚C

E

Temperature / ˚C

G

H

Time / minute

F

Is the freezing point same with the Melting point?A: Yes, both are 79˚C

What is the physical state change in this experiment?A: Liquid naphthalene changes to solid

Where is the point that freezing process started?A: F

Where is the point that freezing process ended?A: G

Why the curve of heating has no change at F-G?A: because the heat energy released during formation of bonds is equal to the heat released to surroundings

Why liquid naphthalene in the boiling tube is cooled inside a conical flask?A: to ensure a uniform cooling

Different solution has different boiling point & freezing point

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Diagram of cooling naphthalene

Q1-Q4 Q5-Q7

Liquid naphthalene

Empty conical flask

2.2 ATOMIC STRUCTURE

The Historical Development Of Atomic Models

• John Dalton – imagine atom as a indivisible tiny ball

• J.J. Thomson – discovered electrons• Ernest Rutherford – discovered proton,

mass of atom concentrated in nucleus• Neils Bohr – proposed the electrons

move in shells around the nucleus• James Chadwick – proved the existence

of neutrons

Subatomic Particle In An Atom


Proton

Neutron

Electron


Proton Electron

Neutron

Nucleus of atom Electron

shells




PROPERTIES PROTON NEUTRON ELECTRON

Symbol

Electric Charge

Relative Mass

Location



Symbol p

Electric Charge

Relative Mass

Location



Symbol p n

Electric Charge

Relative Mass

Location



Symbol p n e-

Electric Charge

Relative Mass

Location



Symbol p n e-

Electric Charge

+1

Relative Mass

Location



Symbol p n e-

Electric Charge

+1 0

Relative Mass

Location



Symbol p n e-

Electric Charge

+1 0 -1

Relative Mass

Location



Symbol p n e-

Electric Charge

+1 0 -1

Relative Mass 1

Location



Symbol p n e-

Electric Charge

+1 0 -1

Relative Mass 1 1

Location



Symbol p n e-

Electric Charge

+1 0 -1

Relative Mass 1 1 1/1240 ≈ 0

Location



Symbol p n e-

Electric Charge

+1 0 -1


Location in the nucleus

atom



Symbol p n e-

Electric Charge

+1 0 -1



atom

in the nucleus

atom



Symbol p n e-

Electric Charge

+1 0 -1



atom

in the nucleus

atom

Electron shells which around the

nucleus atom

40

20Ca

Nucleon number

Proton number

Symbol of Element

-When an atom is neutral , (1.refer ions)

its number of proton = e-

- number of protons = 20 so number of elecrons = 20- 2.electron configuration = 2.8.8.2 valence electron = 2

Symbol of element

3.Next

Electron Configuration

Also known as electron arrangement

How electrons fill into the shells?

Helium HeProton number 2

2

Hydrogen HProton number 1

1

Lithium LiProton number 3

2 . 1

Beryllium BeProton number 4

2 . 2

Boron Bproton number 5

2 . 3

Carbon CProton number 6

2 . 4

Nitrogen NProton number 7

2 . 5

Oxygen OProton number 8

2 . 6

Fluorine FProton number 9

2 . 7

Neon NeProton number 10

2 . 8

Sodium NaProton number 11

2 . 8 . 1

Magnesium MgProton number 12

2 . 8 . 2

Aluminium AlProton number 13

2 . 8 . 3

Silicon SiProton number 14

2 . 8 . 4

Phosphorus PProton number 15

2 . 8 . 5

Sulphur SProton number 16

2 . 8 . 6

Chlorine ClProton number 17

2 . 8 . 7

Argon ArProton number 18

2 . 8 . 8

Potassium KProton number 19

2 . 8 . 8 . 1

Calcium CaProton number 20

2 . 8 . 8 . 2

Conclusion:Conclusion:

1st Shell: max 1st Shell: max 22 e- e-2nd Shell: max 2nd Shell: max 88 e- e-3rd Shell: max 3rd Shell: max 88 e- e-

ARRANGEMENT OF SHELLS IN AN ATOM

NUCLEUS

2 ELECTRONS

8 ELECTRONS

8 ELECTRONS

18 ELECTRONS

1

23

4

Electron arrangement in the carbon atom

C12

6

proton number = 6

number of protons = 6

number of electrons = 6

2 . 4

= electron

nucleus

Number of valence electrons = 4

23

11Na

2 . 8 . 1

number of protons = 11

proton number = 11

number of electrons = 11

= electron

Nucleus

Number of valence electrons = 1 Symbol of element

Try to draw out the electron

arrangement in shells

Draw & state the electron arrangement of the elements below

X15

7Y

24

12Z

39

19

Let us learn some chemical words !!

• Proton number (p) – number of protons in the nucleus of atom

• Nucleon number (p+n)–total number of protons and neutrons in the nucleus of atom

3. Valence electron –the electrons in the outermost shell

4. Electron configuration –arrangement of electron

Repeat them !!Proton number number of protons in the nucleus of

atom

Nucleon numbertotal number of protons and nucleons

in the nucleus of atom

Valence electron the electrons in the outermost shell

Electron configuration –arrangement of electron

Try this out!!!

Elements

ProtonNumber

NucleonNumber

Number of

Neutrons

A 3 7

B 6 12

C 19 10

D 16 16

E 17 18

F 40 20

Q1 Fill in the blanks

Elements

ProtonNumber

NucleonNumber

Number of

Neutrons

A 3 7 4

B 6 12 6

C 9 19 10

D 16 32 16

E 17 35 18

F 20 40 20

Q1 Answers

Elements

Number of

Neutron

Nucleon

Number

Number of

electrons

ElectronConfiguratio

n

A 5 9

B 8 2.6

C 19 2.7

D 14 2.8.3

E 32 16

F 20 40

Q2 Fill in the blanks

Elements

Number of

Neutron

Nucleon

Number

Number of

electrons

ElectronConfiguratio

n

A 5 9 4 2.2

B 8 16 8 2.6

C 10 19 9 2.7

D 14 27 13 2.8.3

E 16 32 16 2.8.6

F 20 40 20 2.8.8.2

Q2 Answers

2.3 ISOTOPES

• Isotopes is just like twins, same genetic but different of DNA

• atoms of the same element with same number of protons but different number of neutrons

What is isotopes?

Examples of Isotopes

• Take a look at Wikipedia isotopes table

• Hydrogen :

• Graphite :

• Oxygen :

1

1

H 3

1

H2

1

H

12

6

C 14

6

C13

6

C

16

8

O18

8

O17

8

O

Isotopes of Hydrogen

Hydrogen :

1

1

H

2

1

H

3

1

H

Properties of isotopesOxygen

Isotopes

No of proton

No of neutron

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O

Properties of isotopes

Oxygen Isotopes

No of proton 8

No of neutron

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes

No of proton 8 8

No of neutron

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes

No of proton 8 8 8

No of neutron

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes

No of proton 16 16 16

No of neutron 16

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes


No of neutron 16 17

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes


No of neutron 16 17 18

No of e-

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16

e- configuration

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16

e- configuration 2.8.6

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16

e- configuration 2.8.6 2.8.6

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16

e- configuration 2.8.6 2.8.6 2.8.6

Valence e-

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16


Valence e- 6

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16


Valence e- 6 6

16

8

O18

8

O17

8

O


Oxygen Isotopes



No of e- 16 16 16


Valence e- 6 6 6

16

8

O18

8

O17

8

O

Conclusion:

• Number of valence electron are same

• The chemical properties also same

• The physical properties might be same, might be different

Try this out!!!

Elements Proton Number Nucleon Number

P 3 7

Q 9 19

R 16 32

S 15 31

T 16 33

U 18 40

Q3. Answer the structure questions

a ) What means proton number?

A: The numbers of proton in the nucleus of an atom

b) What means nucleon number?

A: The numbers of proton & neutron in the nucleus

of an atom

c) Write the electron arrangement for element Q.

A: 2.7

d) How many valence electrons that element Q has?

A: 7

e) How many electron shells that element Q has?

A: two

40

18

U

f) Which pair of elements are isotopes? Explain.

A: R & T. Because they have same proton number but different nucleon number

g) Is R&T have same chemical properties? Why?

A: Yes. Because they have same valence electron

h) How many protons, neutrons, and electrons are

there in atom S?

A: 15 protons, 16 neutrons and 15 electrons

i) Write the symbol to represent atom U. A: 40

18

U

Chapter 2 the structure of the atom

Education

chlorine h

thediffusionof particles

arrangement of particles

o particle theory

gas states diffusion

o molecule ofammonia

gain electron o

element matter