Chemistry Chapter 4-Mr King Eng Sing

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Chemistrymodule

Form 4

SEKOLAH TUANKU ABDUL RAHMAN,

IPOH

Chapter: 4The Periodic Table

of Elements

Name:

Class:

1 | P a g e



4.1 The Periodic Table of Elements

Historical Development of the Periodic Table

** Arrangement of elements in the Periodic Table

a) Elements are arranged in an increasing order of proton number

b) Vertical columns are called group ( Group 1 18)

c) Horizontal rows are called period ( Period 1 7)

d) Elements with similar chemical properties are placed in the same group

e) The group number of the elements with 1 to 2 valence electrons

= the number of valence electrons in its atom.

f) The group number of the elements with 3 to 8 valence electrons

= the number of valence electrons in its atom + 10

g) The period number of an element = the number of shells occupied with

electrons in its atom.

Complete the table below

Element H 1

1He

4

2Li7

3 Be9

4B

11

5C 12

6N 14

7O16

8F 19

9Ne20

10

Electronarrangement

2.1 2.4 2.7

Number of

valence electrons2 8

Group 14 17 Number of shells occupied

2

Period 2

Element Na23

11Mg

24

12Al 27

13 Si28

14P 31

15S 32

16Cl 5.35

17Ar 40

18K 39

19Ca40

20

Electron

arrangement

2.8.1

Number of

valence electrons 6Group 1 16 2 Number of

shells occupied

Period 3 4

An atom of element E has 10 neutrons. The nucleon number of element E is 19. In

which group and period is element E located in the Periodic Table?

2 | P a g e

CHAPTER 4 : PEIODIC TABLE of ELEMENTS

Please pay more attention tothese scientists:

1) LotharMeyer

2) Dmitri Mendeleev*

3) Henry J.G. Moseley*

You are encouraged to

study by yourself for this

contribution of scientist in

the historical development

of the Periodic Table!

Q1

Q2



An atom of element G has 3 shells occupied with electrons. It is placed in group

17 of the Periodic Table. What is the electron arrangement of atom G?

4.2 Group 18 Element

known as noble gases: Helium, neon, argon, krypton, xenon & radon

monoatomic

all noble gases are inert – chemicallt unreactive

** The electron arrangement of noble gases are very stable because the

outermost occupied shells are full

Uses of Group 18 elements:

1. Helium gas – to fill airships and weather balloons

2. Neon gas – used in advertising lights and television tubes

3. Argon gas – to fill light bulbs

4. Krypton gas – used in lasers to repair the retina of the eye

5. Radon gas – treatment of cancer

6. Xenon gas – used for making electron tubes and stroboscopic lamps

4.3 Group 1 Elements (Alkali Metals) Lithium, sodium, potassium, rubidium, caesium & francium

uses of Group 1 elements:

a) Lithium – batteries in calculator, watches and cameras

b) Sodium - 32CO Na in soda-lime glass

c) Potassium - 3 KNO as fertiliser.

* physical properties: softmetals, low densities, low melting & boiling points,

silvery and shiny surfaces, good conductors of heat and electricity

When going down the Group 1, the melting point and boiling point decrease:

melting & Li

boiling points Na

decrease K

Explain why.

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

3 | P a g e

Q3

Helium has duplet electron arrangement. Other noble

gases have octet electron arrangement



** Chemical Properties of Group 1 Elements

1. react vigorously with water to produce alkaline metal hyrdroxide solutions and

hydrogen gas

Example: Li2 + O H 2

2 LiOH 2 + 2 H

Write down the balanced equation when potassium reacts with water _______________________________________________________________

2. react (burn) in oxygen gas rapidly to produce white solid metal oxides

Example: Li4 + 2O O Li

22

Write down the balanced equation when rubidium reacts with oxygen

_______________________________________________________________

3. burn in chlorine gas 2Cl , to form white solid metal chlorides.

Example: Na2 + 2Cl NaCl 2

Write down the balanced equation when potassium reacts with chlorine gas

_______________________________________________________________

** The reactivity of Group 1 elements increases when going down the group.

Explain why.

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

** Potassium reacts more vigorously with water as compared to sodium. Explain.

(Proton number: Na, 11 ; K, 19)

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________ _______________________________________________________________

* Safety Precaustion In Handling Group 1 Elements

1. All alkali metals must be stored in paraffin oil in bottles.

2. Use forceps to take the alkali metals

3. Wear safety goggles and gloves.

4. A small piece of alkali metal is used when conducting experiments.

To Investigate The Chemical Properties of Lithium, Sidum & Potassium

(A)The Reaction of alkali metals With Water, O H 2

Problem Statement: How does the reactivity of Group 1 elements change when

they react with water?

Hypothesis: When going down Group 1, alkali metals become more

reactive in their reactions with water.

Variables: Manipulated variable – Different types of alkali metals

Responding variable – Reactivity of metalsFixed variables – water, size of metals

4 | P a g e

Lithium hydroxide

Lithium

oxide

Q

Q

Q

Q1

Q2

To prevent the alkali react with

air!

ActivityActivity



Procedure:

1. Cut a small piece of lithium using a knife and forceps.

2. Dry the oil on the surface of the lithium with filter paper.

3. Place the lithium slowly onto the water surface in a trough using a forceps.

4. When the reaction stops, test the solution produced with red litmus paper.5. Repeat steps 1 to 4 using sodium and potassium to replace lithium one by one

6. Record your observations.

Data & Observation

Alkali metal Observation

Lithium

Sodium

Potassium

(B) The Reaction of alkali metals With Water, O H 2

Problem Statement: _________________________________________________

_________________________________________________

Hypothesis: ___________________________________________________

___________________________________________________ Variables: Manipulated variable – ________________________________

Responding variable – ________________________________

Fixed variables – ____________________________________

Procedure:

1. Cut a small piece of lithium using a knife and forceps.

2. Dry the oil on the surface of the lithium with filter paper.

3. Put the lithium in a gas jar spoon and heat strongly until it burns.

4. Transfer the gas jar spoon quickly into a gas jar filled with oxyegn gas

5. Observe what happens.6. When the reaction stops, pour 10cm3 of water into the gas jar. Shek the gas jar.

Test the solution formed with red litmus paper.

7. Repeat steps 1 to 6 using sodium and potassium to replace lithium one by one

8. Record your observations.

Data & Observation

Alkali metal Observation

Lithium

Sodium

Potassium

5 | P a g e

You need

to

complete

this table!

This procedure also can beused to test the reaction of

alkali metals with chlorinegas!

This reaction of alkali

metals with chlorine gas will

give the same observations!



Based on your results, arrange the alkali metals in ascending order of

reactivity.

_______________________________________________________________

Write the chemical equations for the reactions between the products from the

combustion of each alkali metal with water.

1. ____________________________________________________________ 2. ____________________________________________________________

3. ____________________________________________________________

Name the substance formed when caesium reacts with chlorine gas. Write the

chemical equation for this reaction.

_______________________________________________________________

4.4 Group 17 Elements (Halogens)

Fluorine, chlorine, bromine, iodine and astatine

uses of Group 17 elements:

1) Chlorine – water treatment, bleaching agent

2) Bromine – weaker bleaching agent

3) Iodine – needed in human thyroid gland to produce hormones

*Physical properties: Low melting and boiling points.

Fluorine: pale yellow gas

Chlorine: greenish-yellow gas

Bromine: reddish-brown gas

Iodine: purplish-black gas

*Remember

2Cl melting and colour of Density2

Br boiling points halogens increases

2 I increase becomes

darker

When going down the Group 17, the melting and boiling points increase. Explain

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

** Chemical Properties of Group 17 Elements

1. react with water to form two acids

Example: 2Cl + O H

2 HCl + HOCl

hydrochloric hypochlorus

acid acid

Write a balanced equation when bromine reacts with water.

__________________________________________________________________

6 | P a g e

Q1

Q2

Q3

All halogens exist as

diatomic molecules!F

2, Cl

2, Br

2, I

2, At

2!!

Why?

Q

Q



2. in gaseous state react with hot iron to form a brown solid, iron (III) halides.

Example: Fe2 + 23 Br 3

2 FeBr

Write a balanced equation when iodine vapour reacts with iron

__________________________________________________________________

3. react with sodium hydroxide solution, NaOH , to form sodium halide,

sodium halite (I) and water

Example: 2 I + NaOH 2 NaI + NaOH + O H

2

Write a balanced equation when chlorine reacts with sodium hydroxide solution

__________________________________________________________________

The reactivity of Group 17 elements decreases when going down the group.

Explain why.

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Chlorine gas reacts more vigorously with hot iron as compared to bromine gas.

Explain (Proton number: Cl, 17 ; Br, 35)

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

7 | P a g e

Q

Q

Q

2

Q

1

Remember…during the

reactions to form

halides, all halogens are

decolourised…

F2is a very

dangerously

reactive

substance!

Do you know why F2

is not used in school

laboratories?

Cl2 gas, Br 2 gas and I2

vapour are poisonous!

We must handle them in

a fume chamber!



To investigate the Chemical properties of Group 17 elements.

The Reaction of halogens with iron

Problem Statement: How does the reactivity of Group 17 elements change when

they react with iron?

Hypothesis: When going down Group 17, the halogens become less reactive in

their reactions with iron.

Variables: Manipulated variable – Types of halogens

Responding variable – Reactivity of halogens

Fixed variable – iron

Procedure:

1. Heat the iron wool in the combustion tube strongly2. When the iron wool becomes red hot, pass the chlorine gas over the hot iron

wool.

3. Observe any changes and record your observation.

4. Repeat steps 1 to 3 using bromine vapour and iodine vapour to replace

chlorine gas one by one.

Data and Observation

Halogens Observation

Chlorine

Bromine

Iodine

What is the function of soda lime in this experiment?

__________________________________________________________________

Why must the iron wool be heated first before the halogens are passed over it?

__________________________________________________________________

Name the products for the reactions between chlorine, bromine and iodine with

iron. Write the chemical equations for these reactions

1. Name:_______________________ Equation:___________________________

2. Name:_______________________ Equation:___________________________

3. Name:_______________________ Equation:___________________________

8 | P a g e

Activity

Complete

this form…

Q1

Q2

Q3



Based on your results, arrange the halogens, 2Cl , 2

Br , 2 I in ascending order of

reactivity.

__________________________________________________________________

Element E is placed below element D in Group 17 of the Periodic Table.

(a). Compare the melting and boiling points of element D with element E. Explainyour answer

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

(b). Write an equation for the reaction between element D and hot iron

_______________________________________________________________

4.5 Elements In A Period

Example: Period 3 in the Periodic Table – Properties of Elements

Element Na Mg Al Si P S Cl Ar

Proton number 11 12 13 14 15 16 17 18

Electron

arrangement

Atomic radius

(pm)

186 160 143 118 110 104 100 94

Physical state at

room

temperature

Solid Solid Solid Solid Solid Solid Gas Gas

Electronegativity 0.9 1.2 1.5 1.8 2.1 2.5 3.0 -

* Across Period 3:

1. The proton number ________________ by one unit from one element to the next

element

2. All the atoms of elements have _______________ shells occupied with electrons.

3. The number of valence electrons in each atom _______________ from 1 to 8.

4. The physical state at room temperature changes from __________ to ___________ 5. The atomic radius (atomic size) of elements ________________.

_________________________________________________________

_________________________________________________________

6. The electronegativity of elements. _______________________

_________________________________________________________

_________________________________________________________

7. The oxides of elements change from basic to acidic properties.

9 | P a g e

Q4

Q5

The measurement of the strengthatom to attract electrons towards

its nucleus

From NaAl, they are

metals, Si is semi metal and

P, S, Cl are non-metals…

Metal oxides exhibit basic

properties and the non-metal

oxide exhibit acidic

properties!



Example:

O Na2 , MgO , 32

O Al , 2SiO 104

O P 2

SO 72OCl

Below are some oxides of elements of Period 3.

(a). Which of these oxides can react with

(i) dilute nitric acid, 3 HNO ?

________________________________________

(ii) sodium hydroxide, NaOH solution?

_______________________________

(b). Based on your answers in (a), what inferences can you make about the

properties of each of the oxides?

_______________________________________________________________

The above show the symbols of lithium, carbon and fluorine.

(a). Which period in the Periodic Table can you find the three elements? Explain.

_______________________________________________________________

(b).Arrange the three elements in order of increasing atomic size.

_______________________________________________________________

(c). Compare the electronegativity of the three elements. Explain your answer.

_______________________________________________________________

_______________________________________________________________

4.6 Transition Elements

elements from Group 3 to Group 12 in the Periodic Table

all are metals

high melting and boiling points ; high densities

good conductors of heat and electricity.

** exhibit three special characteristics:

1. transition elements show different oxidation numbers in their compounds.

Example: Iron: 2 oxidation numbers +2, +3

Copper: 2 oxidation numbers

10 | P a g e

*Sodium oxide, O Na2 *Silicon (IV) oxide, 2

SiO

*Aluminium oxide, 32O Al *Sulphur dioxide, 2

SO

…can be used to

neutralize the acid

solutions!

Shows both acidic

& basic properties !

So… how about

the changes of

metallic

properties? Is it

increase? Or

decrease??Q1

Q2

Li7

3 , C 12

6 , F 19

9



2. transition elements form coloured ions or compounds.

Example: Cu 2+ - blue MnO4- - purple

Fe2+ - green CrO42- - yellow

Fe3+ - brown

3. transition elements and their compounds are useful catalysts.Example:

1. Haber process – Manufacture of ammonia

Catalyst: iron

2. Ostwald process – manufacture of nitric acid

Catalyst: platinum

3. Manufacture of margarine

Catalyst: nickel

4. Contact process – manufacture of sulphuric acid

Catalyst: Vanadium (V) oxide

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Zinc is usually not classified as atransition element because it does not

exhibit the special characteristic of transition elements! Precious stones such as emerald,

rubies, sapphire and jade are beautifuldue to the colours of the transitionelement compounds present in them!

Chemistry Chapter 4-Mr King Eng Sing

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