The_Periodic_Table.pptx

The Periodic Table

Key Words:

PeriodicityAlkali MetalsHalogensNoble gasesGroupPeriodMetals Non-metals

Objectives:

Understand the terms group &period and recall the positions of metals & non-metals in the periodic table

Outcomes:

D-C: Understand the key termsA-B: understand why elements in the same group have similar chemical properties

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Periodic Table Introduction

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Mendeleev

Periodic table

The periodic table arranges all the elements in groups according to their properties.

Horizontal rows are called PERIODS

Vertical columns are called GROUPS

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableFact 1: Elements in the same group have the same number

of electrons in the outer shell (this corresponds to their group number)

E.g. all group 1 metals have __ electron in their outer shell

These elements have __ electrons in their outer shell

These elements have __ electrons in their outer shells

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableFact 2: As you move down through the periods an extra

electron shell is added:

E.g. Lithium has 3 electron in the configuration 2,1

Potassium has 19 electrons in the configuration __,__,__,__

Sodium has 11 electrons in the configuration 2,8,1

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableFact 3: Most of the elements are metals:

These elements are metals

This line divides metals from non-metals

These elements are non-metals

Periodicity Patterns:• Why do elements in the same group have

similar chemical properties?

Because they have the same number of electrons in their outer shells

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H He

Li Be B C N O F Ne

NaMg

Al Si P S Cl Ar

K Ca Fe Ni Cu Zn Br Kr

Ag I Xe

Pt Au Hg

The Periodic TableFact 4: (Most important) All of the elements in the same

group have similar PROPERTIES. This is how I thought of the periodic table in the first place. This is called PERIODICITY.

E.g. consider the group 1 metals. They all:

1) Are soft

2) Can be easily cut with a knife

3) React with water

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Group 1 – The alkali metalsLi

Na

K

Rb

Cs

Fr

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Group 1 – The alkali metals1) These metals all have ___ electron in their outer shell.

Some facts…

3) Reactivity increases as you go _______ the group. This is because the electrons are further away from the _______ every time a _____ is added, so they are given up more easily.

4) They all react with water to form an alkali (hence their name) and __________, e.g:

Words – down, one, shell, hydrogen, nucleus, decreases

Potassium + water potassium hydroxide + hydrogen

2K(s) + 2H2O(l) 2KOH(aq) + H2(g)

2) Density increases as you go down the group, while melting point ________

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Group 0 – The Noble gases

He

Ne

Ar

Kr

Xe

Rn

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Group 0 – The Noble gasesSome facts…

1) All of the noble gases have a full outer shell, so they are very ______2) They all have _____ melting and boiling points

3) They exist as single atoms rather then _________ molecules

4) Helium is ________ then air and is used in balloons and airships (as well as for talking in a silly voice)

5) Argon is used in light bulbs (because it is so unreactive) and argon , krypton and ____ are used in fancy lights

Words – neon, stable, low, diatomic, lighter

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Group 7 – The halogens

F

Cl

Br

I

At

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Group 7 – The HalogensSome facts…

1) Reactivity DECREASES as you go down the group

Decre

asin

g

reactiv

ity

(This is because the electrons are further away from the nucleus and so any extra electrons aren’t attracted as much).

2) They exist as diatomic molecules (so that they both have a full outer shell): Cl Cl

3) Because of this fluorine and chlorine are liquid at room temperature and bromine is a gas

Metals vs non-metalsMetals Non-metals

Tend to be solids Tend to have low melting & boiling points

high melting & boiling points Tend to be brittle as solids

Relatively low densities Don’t usually conduct electricity

Are shiny when polished Poor conductors of heat

Good conductors of heat & electricity Tend to form negative ions

Form positive ions in their compounds Tend to form covalent compounds

Basic oxides – react with acids to give salts and water

Have oxides which are acidic or neutral

Group 1

Key Words:Tarnish

Objectives:

Discuss Group 1 elements

Outcomes:

C: recall the relative reactivities of elements in Group 1B: describe the reactions of these elements with waterA: understand that these reactions provide a basis for their recognition as a family of elements

The Alkali metals:• Francium at the bottom of the group is

radioactivePatterns in the group:• Melting and boiling points are relatively low and

get lower as we go down the group• The densities tend to increase down the group• Metals are very soft (easily cut with knife) –

become softer as we go down the group• They are shiny & silver when first cut – but

tarnish (react) quickly when exposed to air

So reactive!

• So reactive they have to be stored away from air and water

• React quickly to form oxides• React violently with water to form strong

alkaline solutions of metal hydroxides

Brainiac Alkali metals clip:

• http://www.youtube.com/watch?v=m55kgyApYrY

Reactions with Water• All react with water to produce alkaline metal

hydroxide and hydrogen

Metal + cold water metal hydroxide + hydrogen

• The main difference in reactions is how fast they happen

Group 7

Key Words:Tarnish

Objectives:

Discuss Group 7 elements

Outcomes:D: recall their relative reactivitiesC: recall their colours & physical statesB: Describe their reactions with hydrogen

Halogens• Halogen’s means ‘salt-producing’

• When they react with metals they produce many salts

• Halogens are non-metallic

• Have diatomic molecules, e.g. F2, Cl2.

Patterns:• Molecules get larger down the group• Melting and boiling points increase• Fluorine and chlorine are gases• Bromine is a liquid (turns to vapour easily)• Iodine is a solid• Astanine is radioactive• Poor conductors of heat and electricity• When they are solid, their crystals are brittle

Safety:

• Fluorine is dangerously reactive• All the elements have extremely poisonous

vapours• Liquid bromine is very corrosive

Reactions with Hydrogen:• Halogens react with hydrogen to form hydrogen

halides– so, hydrogen chloride, hydrogen fluoride etc

H2(g) + Br2(g) 2HBr(g)

• The hydrogen halides are all steamy, acidic, poisonous gases.

• Covalently bonded• They are soluble in water – produce solutions of

acids e.g. Hydrochloric acid