the-periodic-table-.ppt

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KS4 Chemistry
The Periodic Table

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The Periodic Table
Patterns of behaviour
Patterns and electron structure
Elements and atomic number
Summary activities
Arranging elements
Contents

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What are all substances made of?
…to gold, an unreactive metal.
From chlorine, a poisonous gas…
From sodium, a reactive metal…
There are millions of different substances in the world, but
what are they all made of?
 Elements – the building blocks of all substances.
There are about 100 different elements in a variety of forms.
…to oxygen, a life-giving gas.

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Properties of elements
What is a property of an element?
A property is any characteristic of an element.
For example, here are some properties of sodium:
It would be really useful to be able to predict properties
of elements instead of having to remember them!
Are there any patterns in the properties of elements?
 metallic;
 highly reactive;
 solid but melts easily;
 feels light (low density).

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Properties and atomic number
The properties of an element depend on its atomic number.
What is the atomic number of an element?
Atoms contain three types of particles:
Where are these particles found in an atom?
Particle Mass Charge
proton 1 +1
neutron 1 0
electron almost 0 -1
atomic number = the number of protons in an atom

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What is atomic number?
What are the particles in this helium atom?
What is the atomic number of helium?
neutron
proton electron
2

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Atomic number, charge and electrons
Atoms contain equal numbers of protons and electrons.
This means that atoms are neutral.
What links atomic number and the number of electrons?
9 protons = +9
9 electrons = -9
Total charge = 0
10 neutrons = 0
What is the charge of a fluorine atom?
atomic number = the number of electrons in an atom

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Atomic structure revisited

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The Periodic Table
Summary activities
Arranging elements
Contents

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Periodic table timeline

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Atomic number and patterns of behaviour
H He Li Be B C N O F Ne NaMg Al Si P S Cl Ar K
reactive metals
unreactive gases
reactive gases
If the elements are arranged in order of increasing atomic
number, patterns in their properties can be seen.

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Positions of similar elements
How many elements from one reactive metal to the next?
How many elements from one reactive gas to the next? 8
8
Compare the positions of similar elements:
How many elements from one unreactive gas to the next? 8
reactive metals
unreactive gases
reactive gases

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Mendeleev and the periodic table
Mendeleev created the first modern periodic table by
grouping together elements with similar properties.

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Arranging elements
Arrange these rows so elements with matching properties
are together:
Divide the elements at set intervals into separate rows:
cut here cut here cut here
H He
Li Be B C N O F Ne
NaMg Al Si P S Cl Ar
K

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Arranging elements into columns
When elements are arranged according to their properties
what patterns do you see?
Similar elements go into the same columns.
Hydrogen is an exception – it is best positioned above the
reactive metals.
He
Li Be B C N O F Ne
NaMg Al Si P S Cl Ar
K
H
reactive metals reactive gases unreactive gases
hydrogen
is a special
case

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The periodic table
Arranging all the elements by their atomic number and their
properties led to the creation of…
…the periodic table
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg ? ? ? ? ? ? ?
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Na Mg Al Si P S Cl Ar
Li Be B C N O F Ne
H He

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Missing elements!
In this periodic table the symbols are replaced by atomic
numbers. Some of the numbers are missing – where?
They are called the lanthanides
and actinides and are only
shown on some periodic tables.
87 88 89 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
37 38 39 40 41 42 43 44 45 46 47 38 49 50 51 52 53 54
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
11 12 13 14 15 16 17 18
3 4 5 6 7 8 9 10
1 2
Two more rows of elements fit here.

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The elements in the periodic table

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Columns of elements
What are columns of elements called?
groups
Rb Sr Y Zr NbMo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Li Be B C N O F Ne
H He
1 2 4
3 5 6 0
7

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Rows of elements
periods
What are rows of elements called?
Li Be B C N O F Ne
H He
1
2
3
4
5
6
7

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The Periodic Table
Summary activities
Arranging elements
Contents

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Patterns: metals and non-metals
on the right (except hydrogen)
Where are these different types of elements grouped
together in the periodic table?
 metals
 non-metals
between metals and non-metals
 metalloids
on the left and centre
Can you name a metalloid element?
Metalloids aren’t a type of rock music fan!
Metalloids have some properties similar to metals and other
properties similar to non-metals.

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Metals, non-metals and metalloids

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Patterns: physical state
Only two elements are liquids at room temperature.
What are they?
 liquids
Where are these elements of different states grouped
together in the periodic table?
in the middle and on the right
 solids
on the far right (except hydrogen)
 gases
on the left, in the centre and on the right
 bromine and mercury

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Solids, liquids and gases

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Patterns: reactivity of metals
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po
Rb Sr Y Zr NbMo Tc Ru Rh Pd Ag Cd In Sn
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga
Na Mg Al
Li Be
What happens to the reactivity of metals down a group?
Which is the most reactive metal?
increase in reactivity
increase
in
reactivity
What happens to the reactivity of metals along a period?

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Which metal is more reactive?

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Patterns: reactivity of non-metals
increase in reactivity
Group 0 elements are the most unreactive of all elements.
For the remaining non-metals and metalloids, reactivity
increases up a group and along a period from left to right.
Which is the
most reactive
non-metal/
metalloid?
At Rn
Sb Te I Xe
Ge As Se Br Kr
Si P S Cl Ar
B C N O F Ne
He
increase
in
reactivity
unreactive

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Which non-metal is more reactive?

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The Periodic Table
Summary activities
Arranging elements
Contents

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Patterns, atomic number and electrons
What links atomic number and
the properties of elements?
The periodic table shows that patterns in the properties of
elements are linked to atomic number.
electrons
Li Be B C N O F Ne
H He

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Atomic number and electrons
atomic number = number of protons
atomic number = number of electrons
The properties of elements are hugely influenced by the
number and arrangement of electrons in the atom.
What links atomic number and the number of electrons in
an atom?
As atomic number increases by one, the number of electrons
also increases by one.
This means that the elements in the periodic table are also
arranged in order of the number of electrons.
number of protons = number of electrons

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Electron shells
Electrons are arranged in shells around an atom’s nucleus.
This electron arrangement is written as 2,8,8.
1st shell holds
a maximum of
2 electrons
2nd shell holds
a maximum of
8 electrons
3rd shell holds
a maximum of
8 electrons
Each shell has a maximum number of electrons that it can
hold. Electrons will fill the shells nearest the nucleus first.

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Electrons in period 1
Elements in period 1 only have electrons in the first shell.
Why are there only two elements in period 1?
The first shell can only hold a maximum of two electrons,
so period 1 only includes the elements hydrogen and helium.
What is special about the outer shell of helium?
1 2
H He
1 2 4
3 5 6 0
7
1

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Elements in period 2 all have a complete first shell.
The second shell is completed one electron at a time going
across the period from left to right.
What is special about the outer shell of neon?
2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8
Li Be B C N O F Ne
1 2 4
3 5 6 0
7
What happens to electrons in the second shell in period 2?
2

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2,8,1 2,8,2 2,8,3 2,8,4 2,8,5 2,8,6 2,8,7 2,8,8
Elements in period 3 have complete first and second shells.
The third shell is completed one electron at a time going
across the period from left to right.
What happens to electrons in the third shell in period 3?
1 2 4
3 5 6 0
7
What is special about the outer shell of argon?
3

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Patterns of electron arrangements
Consider the electron arrangements of the first 20 elements
in the periodic table.
What is the pattern of outer shell electrons in a group?
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 2 4
3 5 6 0
7
1
2
3
4
2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8
1 2
2,8,8,1 2,8,8,2
What is the pattern of outer shell electrons across a period?
What is the pattern of full electron shells in a group?

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Electron trends in the periodic table
Trends down a group:
The point at which a new period starts is the point at which
electrons begin to fill a new shell.
The number of a group is the same as the number of
electrons in the outer shell of elements in that group,
except for group 0.
 the number of outer shell electrons is the same;
 the number of complete electron shells increases by one.
 the number of outer shell electrons increases by one;
Trends across a period:
 the number of complete electron shells stays the same.

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Electrons and groups

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Groups and periods

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What’s the electron arrangement?

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Names of groups in the periodic table

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The Periodic Table
Summary activities
Arranging elements
Contents

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Glossary
 atomic number – The number of protons in an atom.
Sometimes called the proton number.
 electron arrangement – A shorthand way of writing the
number of electrons in an atom’s electron shells.
 element – A substance made up of only one type of atom.
 group – A column in the periodic table containing elements
with the same number of outer shell electrons and similar
chemical properties.
 period – A row in the periodic table containing elements
with the same number of full electron shells.
 periodic table – The table that lists all the elements in
order of increasing atomic number, arranged into groups and
periods.
 property – Any characteristic of an element.

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Anagrams

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Matching elements and groups

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Multiple-choice quiz

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