© boardworks ltd 2003 the periodic table. © boardworks ltd 2003 a slide contains teacher’s notes...

© Boardworks Ltd 2003

THE PERIODIC TABLE


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Variety

• There are millions of substances in the world.• All these substances are made from about 100

different building blocks called elements.• These elements take a huge variety of forms:

to unreactive metals like gold

To the air we breathe

From poison gases like chlorine

From reactive metals like sodium


Properties of Elements

In science the word propertiesproperties means, what the substance is like. For example, here are some properties of sodium:

–Metallic–Highly reactive–Solid but melts easily–Low density (light)

It would be really useful to be able to predict properties of elements instead of having to remember them!


Atomic Number

Scientists found that the properties of elements seem to depend upon atomic number.

Atoms contain three types of particles:

ParticleParticle ChargeCharge Relative MassRelative Mass

Protons +1 1

Neutrons 0 1

Electrons -1 0.0005

Atomic number = the number of protons in an atom.


Atomic Number and Electrons

In elements the atoms contain equal numbers of protons and electrons.

It follows that for an element the atomic number is equal both to the number of protons and to the number of electrons.

FluorineFluorine

9 protons 9+

9 electrons 9-

10 neutrons 0

Total Charge 0

1919

FF99

Atomic Number

Symbol

Atomic Mass


Atomic Number and Patterns

When scientists arranged elements in order of increasing atomic number (below) they found patterns in the properties.

KH Li NaBe Mg Al PN O S ClF Ne ArSiHe B C

Reactive Metals Unreactive GasesReactive Gases


Do similar elements occur at regular intervals?

Count the number of elements to get from one reactive gas to the next?

Count the number of elements to get from one reactive metal to the next?

KH Li NaBe Mg Al PN O S ClF Ne ArSiHe B C191 3 114 12 13 157 8 16 179 10 18142 5 6

Reactive Metals Reactive Gases

8

8


Putting elements in a table

If we divide the elements up and arrange them into a table we easily get patterns.

K

NaMg Al P S Cl ArSi

H He

Li Be N O F NeB C


191 3 114 12 13 157 8 16 179 10 18142 5 6

Cut here and here and here

And arrange these strips below each other



When we rearrange the strips elements that are similar go into the same columns.

Al P SSi

Be N OB C

Mg

Li

K

Na

Reactive Metals

Ar

Ne

HeUnreactive Gases

Cl

F

Reactive Gases

K19

NaMg Al P S Cl ArSi11 12 13 15 16 17 1814

H He1 2

Li Be N O F NeB C3 4 7 8 9 105 6


Carrying on building up the elements by atomic number led to the creation of the periodic table shown below.

H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg

V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa Kr

Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh

Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt

Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As



Groups – columns of elements

Downward columns are called groups.groups.

H

Li

Na

K

Rb

Cs

Fr

Gro

up

1

Be

Mg

Ca

Sr

Ba

Ra

Gro

up

2

Ga

In

Tl

Al

B

Gro

up

3

Ge

Sn

Pb

Si

C

Gro

up

4

Sb

Bi

P

N

As

Gro

up

5

Se

Te

Po

O

S

Gro

up

6

He

Kr

Ne

Ar

Rn

Xe

Gro

up

0

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Y Zr Nb Mo Tc Ru Pd Ag CdRh

Hf Ta W Re Os Ir Au HgLa Pt

Rf Db Sg Bh Hs Mt ? ?Ac ?

Transition Elements

Means in-between

Br

At

Cl

F

I

Gro

up

7


Periods – rows of elements

Rows of elements are called periodsperiods.

H He1

Li Be N O F NeB C2

Na Mg Al P S Cl ArSi3

K Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa KrAs4

Rb Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh I Xe5

Cs Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt Rn6

Fr Ra Rf Db Sg Bh Hs Mt ? ?Ac ?7

Period Number


H He1

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

B C

As

1 2 3 4 5 6 7 0

2

4

3

5

6

7

G p

Pd

What’s the group and Period?

Mg

C

Group 2 Period 3Group 4 Period 2Group 7 Period 3

Cl

K

Group 1 Period 4MgCClK


Missing elements!

Below the chemical symbol have been replaced by atomic numbers. You will see some are missing!

1

3

11

19

37

55

87

4

21 22

12

23 24 25 26 27 28 29 30 31 32 34 3520 36

39 40 41 42 43 44 46 47 48 49 50 5138 5245

56 72 73 74 75 76 77 79 80 81 82 83 8457 8578

88 104105106107108109 11111289 110

13 15

7 8

16 17

9 10

18

86

53

14

54

2

5 6

33

Two further series of elements should go here but are only shown on some Periodic Tables. They are called the lanthanides and actinides.


Patterns 1. Metals and Non-metals

Metals are on the left and centre.

Non-metals are mostly on the right

In between are metalloids.These are like metals in some ways and like no-metals in others.


Patterns 1. Metals and Non-metals


Say whether these elements are metals, non-metals or metalloids.

H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As

Silicon (Si) MetalloidFrancium (Fr) MetalScandium (Sc) MetalKrypton (Kr) Non-metalCobalt (Co) Metal


Physical state means – is it a solid, liquid or gas.

There are only 2 liquid elements.

Notice how most of the gases are on the far right.

Physical State


Physical State


Say whether these elements are solids, liquids or gases.

H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As

Krypton (Kr) Gas

Kr

Niobium (Nb) Solid

Nb

Barium (Ba)

Ba

SolidNitrogen (N)

N

GasBromine (Br)

Br

Liquid


Patterns 2. Reactivity of Metals

• As a general, but not perfect, rule: the further to the left and the further down the table - the more reactive the metal is.

More Reactive

More R

eactive


Potassium (K) or Lithium (Li)

Which metal is most reactive?

H

Li

Na

KRbCs

Fr

Be

Sc Ti

Mg

V Cr MnFe Co Ni Cu ZnGaGeCaY Zr NbMoTc Ru Pd AgCd In Sn SbSr Rh

Ba Hf Ta W ReOs Ir AuHg Tl Pb Bi PoLa Pt

Ra Rf DbSg Bh Hs Mt ? ?Ac ?

Al

KCalcium (Ca) or Magnesium (Mg) CaCalcium (Ca) or Iron (Fe) CaCopper (Cu) or Barium (Ba) Ba


Patterns 3. Reactivity of Non-Metals

This is more complicated.

At the very end of the periodic table is the most unreactive group of elements in the table.

Apart from that – the further up and the further right – the more reactive the non-metal.

More reactive

Mor

e re

activ

e


Neon (Ne) or Iodine (I)

Which non-metal is most reactive?

Se Br Kr

Te

At

P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As

IOxygen (O) or Silicon (Si) OFluorine (F) or Chlorine (Cl) FCarbon (C) or Oxygen (O) O


Patterns and Electron Structures

• The physical and chemical properties of elements are hugely influenced by the number and arrangement of electrons in the atom.

• This is why patterns in properties are linked to atomic number.

• If the atomic number increases by one it means that the atom has one extra electron.

1

HH1

4

HeHe2

7

LiLi3

9

BeBe4

10

BB5

Each element has one more electron

Atomic number = number of protons

For atoms of an element it is also = number of electrons


• The places where we start a new period is to do with the arrangement of the electrons.

• It is the point at which electrons start entering a new shell further from the nucleus.


191 3 114 12 13 157 8 16 179 10 18142 5 6

Cut here and here and here

We shall look at these electron arrangements in the next few slides.

Patterns and Electron Structures


Patterns of Electron Arrangements

We can imagine building up atoms by adding protons, neutrons and electrons as we cross the periodic table.

Sc Ti V Cr MnFe Co Ni Cu Zn2,8,8,1 2,8,8,2

2,8,1 2,8,2 2,8,3 2,8,5 2,8,6 2,8,7 2,8,82,8,4

1 2

2,1 2,2 2,5 2,6 2,7 2,82,3 2,4

22,88,88,22

Electronsin 1st shell Electrons

in 2nd shellElectronsin 3rd shell

Electronsin 4th shell


H He1

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

B C

As

1 2 3 4 5 6 7 0

2

4

3

5

6

7

G p

Pd

What’s the electron arrangement

Mg

C

2.8.22.42.8.7

Cl

K

2.8.8.1MgCClK


1 72 3 4 5 6 8

Arrangement of Electrons

1

2

3

Click on action buttons to reveal how electron configuration is built-up.The transition metals

Skip this


1 72 3 4 5 6 8

1

Electrons in Period 1

1 2

Skip this



1 72 3 4 5 6 8

2

2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8

This atom isspecial it has a complete outer shell

Elements in the second period contain 2 electrons in the first shell (complete) and the second shell is completed one electron at a time as you cross the period from left to right.

Skip this


3

2,8,1 2,8,2 2,8,3 2,8,4 2,8,5 2,8,6 2,8,7 2,8,8

1 72 3 4 5 6 8


Elements in the third period have complete first and second shells. The third shell is completed one electron at a time as you cross the period from left to right.

Skip this


1

1

2

3

1

2,1

2,8,1

Group 1 Elements

Group 1 elements have 1 electron in the outermost shell which they lose in chemical reactions.The outer electron is further from the nucleus and so more easily lost as you go down the group. This is why reactivity increases going downwards

Skip this


2

2,2

2,8,2

Group 2 Elements

In chemical reactions metals tend to lose their outer shell electrons to form positive ions.

So, these elements all form ions with a 2+ charge.

The further the outer shell is from the nucleus the more easily electrons are lost.

Skip this


3

2,3

2,8,3

Group 3 Elements

Metals lose their outer electrons to form ions. The charge on the ion produced by Group 3 metals will be +3.

Skip this


4

2,4

2,8,4

Group 4 Elements

The elements at the top of Group 4 are non-metals. They bond covalently, i.e. by sharing electrons with another atom.

Skip this


5

2,5

2,8,5

Group 5 Elements

The number of electrons in the outermost shell is the same as the group number.

They need 3 more electrons to achieve a full electron shell.

Skip this


6

2,6

2,8,6

Group 6 Elements

The atoms in Group 6 form negative ions (2-) by the addition of two extra electrons. This completes their outer most shell.

Skip this


7

2,7

2,8,7

Group 7 Elements

Group 7 elements form 1- ions by the addition of 1 extra electron.

They are most reactive at the top of the group because incoming electrons are pulled into shells that are closer to the nucleus.

Skip this


8

2,8

2,8,8

Group 0 Elements

The elements in Group 8 (or 0) have complete outer shells.

They are very unreactive and are called NOBLE (or inert) GASES.

2

Skip this


Periodic Table and Reactivity

The fact that in each group the number of outer shell electrons is the same leads to similar types of chemical reactivity.

For example, all group 1 elements react with water to give hydrogen and an alkali.

The fact that the outer shell electrons get progressively further from the nucleus leads to trends (patterns).

For example, Group 1 elements get more reactive as you go down the group.


Broad Types of Element


In the Periodic Table elements are arranged in order of?

A. Atomic massB. Atomic numberC. DensityD. Boiling point


Neutral atoms of an element contain?

A. Equal numbers of protons and neutronsB. Equal numbers of electrons and neutronsC. Equal numbers of protons and electronsD. Equal numbers of protons, neutrons and

electrons


A vertical collection of elements in the Periodic Table are called?

A. GroupsB. PeriodsC. ColumnsD. Gases


A horizontal collection of elements in the Periodic Table are called?

A.GroupsB.PeriodsC.RowsD.Gases


In the Periodic Table gases occur?

A. On the leftB. On the left and middleC. On the right and middleD. On the right


In the Periodic Table metals occur?

A. On the leftB. On the left and middleC. On the right and middleD. On the Right


The Group 7 Elements are also called?

A. The halogensB. The transition elementsC. The alkali metalsD. The noble gases


The Group 1 Elements are also called?

A. The halogensB. The transition elementsC. The alkali metalsD. The noble gases


In the Periodic Table metals get more reactive going towards?

A. Top leftB. Top rightC. Bottom leftD. Bottom right


Which of these electron arrangements could be a noble gas?

A. 2.1, B. 2.5C. 2.7D. 2.8


Which of these electron arrangements could be a halogen?

A. 2.1, B. 2.5C. 2.7D. 2.8


Teacher Resources


THE PERIODIC TABLE

H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As


H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg





Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As

© boardworks ltd 2003 the periodic table. © boardworks ltd 2003 a slide contains teacher’s notes...

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