analyzing group 1 element

8/7/2019 Analyzing Group 1 Element

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CHAPTER 4

PERIODIC TABLE OF ELEMENTS


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Learning Objective

Describechangesinreactivity of Group 1

elements downthegroup.

Predict physicaland chemical propertiesof otherelementin Group 1.

Statethesafety precaution whenhandling

Group 1 elements.


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PERIODIC TABLE OF ELEMENTSGroup 1 elements


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INTRODUCTION

Sodium

Na

Potassium

KLithium

Li


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ELEMENTS IN GROUP 1

1. Alkalimetals

2. Lithium,sodium, potassium,rubidium,caesium, francium3. Eachelementcontains 1 valencee-

4. Physical properties:

- good conductorofheatnelectricity

- Softmetal- Grey,silvery,shinysurfacemetal

- Low melting pointsn boiling pointscompared to heavymetalssuchasiron

- Low densities float on water..

5. Whengoing downgroup1- Theatomicsizeincreases no ofshells occupied withe- increases

- Themeltingand boiling point decrease sizeincrease force ofattraction

become weaker

- The density ofelementsincreases.


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CHEMICAL PROPERTIES OF GROUP 1

1. 1. valenceelectron

2. Duringchemicalreaction,it willlosethevalencee- to formanion

withacharge of +1

-achievingthestable duplet oroctete- arrangement

3. Elementsingroup 1 areveryreactivemetals

4. Alkalimetalshavesimilarchemical properties but differinreactivity

5. Thereactivityincreases downthegroup.

-depends onhow easilyitcanloseitsvalencee-


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1. Thereactivity will be observe whenthereaction ofthe

Group 1 elements withwater, oxygen and chlorine.

2. Reaction oflithium,sodiumand potassium with:-Water( X + H2O XOH + H2 ) XOH- alkalinemetal

hydroxide

-Oxygen ( X + O2 2X20)- whitesolid metal oxides* X20 + H2O 2XOH

-Halogen ( 2X + Y2 2XY )

A) Changes in reactivity of group 1 elements

down the group


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Reaction with water

Lithium

Sodium

Potassium

2Li + 2H20 2LiOH + H

2

2Na + a2H20 2NaOH + H2Natrium water Natrium Hydroxide Hydrogen

2K + 2H20 2KOH + H2Potassium water Potassium Hydroxide Hydrogen

Lithium water Lithium Hydroxide Hydrogen

-Reactionmovesslowly.

-Lookred flame.

-Turnsred litmusto blue.

-Reactionmove quickly.

-Look brightyellow flame.


-Reactionmovevirgorously.

-Look brilliant purple flame.



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Reaction with oxygen

Lithium

Sodium

Potassium

4Li + O2 2Li20Lithium Oxygen Lithium Oxide

-Burn withred flameslowly.

4Na + O2 2Na20Sodium Oxygen Sodium Oxide

-Burn with brightyellow quicklyand clear.

4K + O2 2K20Potassium Oxygen Potassium Oxide

-Burnveryvigorously with brilliant purple flame.


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Reaction with chlorineLithium

Sodium

Potassium

2Na + Cl2 2NaCl

Sodium Chlorine Sodium Chloride

-Burn quickly with a bright yellow flame.

-Produce white solid.

2Li + Cl2

2LiCl

Lithium Chlorine Lithium Chloride

-Burn slowly in red flame.

-Produce white solid.

2K + Cl2 2KCl

Potassium Chlorine Potassium Chloride

-Burn vigorously with a brilliant purple flame.

-Produces awhite solid .


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3. Lithium,sodiumand potassium whichare

Group 1 elements:

Have only one electron valence in the outer shell. So,they have the same chemical reaction.


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B) Physical and chemical properties

of other element in group 1


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3) Thedensity ofgroup 1elementsincreases when

going downthegroup.

2) Thehardness,melting point

and boiling point decreases

whengoing downthegroup.

1) Soft metals

So,the Group 1 elementsare:


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C) Safety precautions when handlingGroup 1 elements


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Conclusion

Thegroup 1 elementscanreacts with water,chlorineand oxygen.

Group 1 elementshavethesamechemical properties becausetheyhave oneelectronvalencein outershell.

Wemustcarefully whenhandling Group 1 elements becausetheyareveryreactivemetals.

Foradditionalreferences:

http://periodic.lanl.gov/default.htm

http://www.theodoregray.com/PeriodicTable/

analyzing group 1 element

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