Download - KS3 Chemistry
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KS3 Chemistry
8E Atoms and Elements
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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How many different substances are there?
There are millions of different substances!What are they all made of?
How many different substances
can you think of?
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All substances are made of atoms
All substances are made of very tiny particles called atoms.
hydrogen and oxygen atoms
carbon and hydrogen atoms
carbon, nitrogen, hydrogen, oxygen and sulphur atoms
iron, aluminium, silicon, oxygen
and boron atoms
Many substances are made up of different types of atoms.
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What is an element?
All substances are made of very tiny particles called atoms.
The elements are the simplest substances in the universe.
The elements are the building blocks of all other substances.
copper
carbon
There are about one hundred substances that are made up of just one type of atom. These are the elements.
helium
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An element is a substance made up of only one type of atom.
Atoms in elements
The element Copper is an
element made up of copper atoms only.
The element Carbon is an
element made up ofcarbon atoms only.
The element Helium is an
element made up ofhelium atoms only.
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Atoms and molecules of elements
In some elements, the atoms are joined in groups of two or more. A particle containing atoms grouped in this way is called a molecule.
An element is a substance made up of only one type of atom.
Other elements, that contain atoms joined in molecules are hydrogen, nitrogen, chlorine and bromine.
Oxygen is an element made up of oxygen atoms only.
How many atoms are there in an
oxygen molecule?
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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The symbol for many of the more common elements uses just the first letter of the name.
Introducing chemical symbols
A standard set of symbols is used to represent elements:
hydrogen
H =carbonC =fluorineF =
oxygenO =nitrogen
N =
Others elements have the first two letters.
lithiumLi =aluminium
Al =heliumHe
=
Some of the symbols are not always as you might expect.
leadPb =goldAu =silver
Ag =
iodineI =
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Symbols as an international language
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How to write symbols for elements
Two important rules should be followed when writing the symbols of elements so that there is no confusion.
1. The first letter of an element’s symbol is always a capital letter.
2. If there are two letters in the element’s symbol, the second letter is always a small letter.
e.g. N (not n) for
nitrogen
e.g. Co (not CO) for cobalt
No, Watson! It was carbon monoxide
poisoning – not cobalt.
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Chemical symbols game
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The Story of ‘The Kid’
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1. Board game: carbon, helium, two sulphurs
2. Relative: sulphur, oxygen, nitrogen 3. Fuel: carbon, oxygen, aluminium
4. Group of fish: sulphur, hydrogen, oxygen, aluminium
5. For the rubbish: boron, iodine, nitrogen
CHeSS
SON
COAl
SHOAl
BIN
Spelling with symbols activity
Write down the symbols for each element listed and use these to spell out a word that matches the clue.
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In some elements, the atoms are joined together and form molecules. Combining the symbols of the atoms in a molecule gives you the formula of the molecule.
What is the formula for the molecules in each element?
Symbols for molecules of elements
nitrogen
oxygen
N2
O2There are groups of
two atoms in each
molecule.
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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Arranging elements
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antimony (Sb)
Is this element a or a ?
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
AsFeFe
Mg SPMg SP
CuCu
metal non-metal
IISb
Hard to say!
Sb
Metal or non-metal?
iodine (I)iron (Fe)copper (Cu)phosphorus (P)sulfur (S)magnesium (Mg)
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Metals and non-metals in the periodic table
The periodic table is a list of all the known elements which are arranged according to the similarities in their properties.
Non-metals are mostly on the right.
Metals are on the left and in the centre.
What type of elements are between metals and non-metals?
Xe
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Types of elements in the periodic table
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Metal, non-metal or metalloid?
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
silicon (Si) metalloidfrancium (Fr) metalscandium (Sc) metalkrypton (Kr) non-metalcobalt (Co) metal
What aremetalloids?
Which side are the non-metals on?
Which side are the
metals on?
Metalloids sometimes behave like metals and
sometimes like non-metals.
Metals are on the left and in
the centre.
Non-metals are mostly
on the right.
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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Combining elements
How is possible to have so many different materials from a limited number of elements?
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Combining elements
How do you get so many different cheeses?
What is the key ingredient in all cheeses?
Milk is combined with a small number of ingredients under different conditions to make a huge number of different cheeses.
In a similar way, a small number of elements can be combined in many different ways to make a huge
number of different compounds.
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What is a compound?
A compound is the substance produced when two or more elements combine in a chemical reaction.
A compound is always made up of two or moredifferent types of atom.
Two elements, hydrogen (H) and oxygen (O), combine to make the compound, water.
Which two elements combine to make the compound carbon dioxide?
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Making a compound – carbon dioxide
A compound has very different properties to the elements from which it is made.
carbon dioxide
A colourless gas which is used to put out fires.
to make
carbon
A black solid which can be
used as a fuel.
combines with
compound
elementsoxygen
A colourless gas which is essential
for life.
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Making a compound – water
What are the elements which make up water? In what ways are the elements different to their compound?
to makecombines with
compound
elementswater
A liquid which is essential to our
lives and has many different uses.
hydrogen
A colourless gas which is used in hot air balloons.
A colourless gas which is essential
for life.
oxygen
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Element or compound?
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Element or compound?
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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Chemical reaction to make water
Elements combine with each other to make new substances called compounds.
In a chemical reaction new substances are formed.
hydrogen
The substances which combine in a reaction are the reactants. The new substances produced in a reaction are the products.
Compounds can also combine with elements or other
The products have different properties to the reactants fromwhich they are formed.
water
compounds to make new compounds.
+oxygen
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When the two elements, hydrogen and oxygen, combine in a chemical reaction,
Atoms joining in a chemical reaction
In a chemical reaction, the atoms in the reactants become joined in different ways and this is how
new substances are formed.
hydrogen oxygen water+
+H H
H HO O
the hydrogen and oxygen atoms do not just mix together they become joined to one another.
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8E Atoms and Elements
Elements in the periodic table
Summary activities
Chemical reactions
What are atoms and elements?
Symbols for elements
Contents
Making compounds
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Glossary
atom – The smallest particle that can exist on its own.
compound – Substance made up of two or more different elements that are chemically joined together.
element – Substance made up of only one type of atom.
formula – The symbols and numbers that represent the atoms in a substance.
molecule – Two or more atoms that are chemically joined together.
periodic table – Table in which all known elements are arranged based on their properties.
symbol – One or two letters that represent an element.
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Anagrams
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Multiple-choice quiz