the periodic table...the periodic table shows that patterns in the properties of elements are linked...
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The Periodic Table
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The Periodic Table
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The periodic table
There are approximately 100 naturally occurring elements.
All the known elements are shown in the periodic table.
Can you spot any patterns in how the
elements are arranged in the periodic table?
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Who invented the periodic table?
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Mendeleev and the periodic table
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How are the elements arranged?
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Arranging the periodic table
Arranging all the elements by their atomic number and their
properties led to the creation of the periodic table.
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Missing elements!
In this periodic table the symbols are replaced by atomic
numbers. Some of the numbers are missing – where?
Two more rows of elements fit here.
They are called the lanthanides and actinides.
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Metals, non-metals and metalloids 1
Metals are on the left and in the centre of the periodic table.
Non-metals are located mostly on the right.
Metalloids are located between metals and non-metals in
the periodic table. Metalloids sometimes behave like metals
and sometimes like non-metals.
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Metals, non-metals and metalloids 2
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Columns of elements
What are columns of elements called?
groups1 2 43 5 6 07
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Rows of elements
periodsWhat are rows of elements called?
1
2
3
4
5
6
7
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The Periodic Table
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Complete the sentences
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Patterns: reactivity of metals
What happens to the reactivity of metals down a group?
Which is the most reactive metal?
What happens to the reactivity of metals along a period?
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Which metal is more reactive?
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Reacting with water
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Patterns: reactivity of non-metals
Group 0 elements (noble
gases) are the most
unreactive of all
elements.
For the remaining
non-metals, reactivity
increases up a group
and along a period from
left to right.
Which is the most reactive non-metal? very
unreactive
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Which non-metal is more reactive?
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Halogen reaction with iron wool
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The Periodic Table
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Patterns, atomic number and electrons
The periodic table shows that patterns in the properties of
elements are linked to atomic number.
atomic number = number of protons
atomic number = number of electrons
number of protons = number of electrons
Therefore, 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.
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How are electrons arranged?
Electrons are arranged in shells around an atom’s nucleus. (The shells can also be called energy levels.)
This electron arrangement is written as 2,8,8.
1st shell holdsa maximum of
2 electrons
2nd shell holds
a maximum of
8 electrons
Each shell has a maximum number of electrons that it is able
to hold. Electrons fill the shells nearest the nucleus first.
3rd shell holds
a maximum of
8 electrons
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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 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 43 5 6 07
1
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Electrons in period 2
Elements in period 2 all have a complete first shell.
The second shell is filled 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 43 5 6 07
What happens to electrons in the second shell in period 2?
2
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Electrons in period 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
Elements in period 3 have complete first and second shells.
The third shell is filled across the period from left to right.
What happens to electrons in the third shell in period 3?
Na Mg Al Si P S Cl Ar
1 2 43 5 6 07
What is special about the outer shell of argon?
3
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Patterns of electron arrangement
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 43 5 6 07
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
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Periodic table and electron structure
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Glossary
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Anagrams
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Multiple-choice quiz