Exam tip; A symbol represents 1 atom of an element.
Key words; Atom, Compound, Electron, Element, Symbol
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Learning Objectives
By the end of the lesson I can:
•Recall that all substances are made up of atoms
•Describe and explain what is inside an atom
•Describe how elements contain only one type of atom
•Understand that symbols are used for atoms to show what
happens in chemical reactions.
•Know that all 100 known elements are listed on the periodic
table and groups have similar properties
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
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.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Atoms – the building blocks
All substances are made from very tiny particles called atoms.
John Dalton had ideas about the
existence of atoms about 200 years ago
but only relatively recently have special
microscopes (called electron
microscopes) been invented that can
‘see’ atoms.
The yellow blobs in this image are
individual gold atoms, as seen through
an electron microscope.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Daltons Atomic Theory
• All matter is made Devise
up of tinythe
particles called atoms.
• Atoms cannot be created or destroyed (as stated in
LAWof OF
the Law of Conservation
matter)
OF
• All atoms ofCONSERVATION
an element are THE SAME
• Atoms of one element MASS
are completely different to the
atoms of another element
(2 mins)
• Atoms combine in small numbers to form molecules
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Even smaller particles
Scientists now know that atoms are actually made from
three even smaller particles:
proton
neutron
electron
These particles are so small weighing
them in grams is meaningless
So instead we say Protons and
Neutrons have a mass of one unit,
whereas, electrons are smaller, about
1/2000 of a unit (effectively nothing)
Some particles have an electrical
charge
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Whilst this is still not completely accurate, this is
how we draw an atom when we are learning
science at secondary school
Draw an atom
and try to
label it with
the 3 sub
atomic
components
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
This is a bit more accurate because we have no
idea of where the electrons are at any one time –
they are in a cloud called the electron cloud.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Inside an atom
Atoms always
have the same
number of 1. Draw an atom and annotate it
protons and
2. Use a ‘METAPHOR’
electrons,
to explain the atom concept
making them to a 10 year old child (year 6)
neutral
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Imagine a hoola hoop
Now imagine a ball
somewhere in the
middle of the hoop.
This represents the
nucleus
Now imagine a car
running round the
outside somewhere.
This represents an
electrons
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
What is left is a very simple
and not completely accurate
model of an atom
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Include annotated detail
1
1
1/2000
+1
0
-1
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Elements
• There are about 100 different elements listed on the periodic
table of elements
• Elements are madeHow
up ofcan
justyou
onefind
type of atom.
the number
• Each atom in an element
has the same number of protons.
of neutrons?
• Different elements have different numbers of protons in
their atoms.
• The atomic number of an element is its number of protons.
can you find
• The mass number ofHow
an element
is its number of protons and
the number
neutrons
of ELECTRONS?
• There is an equal number of protons and electrons
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
O
Symbols
Na
• Every element has a symbol as a shorthand way
of writing it down.
• Symbols have one or two letters.
• The first letter is always a capital letter. The
second is always lower case.
Cl
K
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Write down the symbols for each element listed and
use these to spell out a word that matches the clue.
1. Board game: carbon, helium, two sulphurs
CHeSS
2. Relative: sulphur, oxygen, nitrogen
SON
3. Fuel: carbon, oxygen, aluminium
COAl
4. Group of fish: sulphur, hydrogen, oxygen,
aluminium
SHOAl
5. For the rubbish: boron, iodine, nitrogen
BIN
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
An element is a substance made up of only one type of atom.
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.
Oxygen is an element
made up of oxygen
atoms only.
How many atoms are
there in an oxygen
molecule?
Other elements, that contain atoms joined in molecules are
hydrogen, nitrogen, chlorine and bromine.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
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?
oxygen
nitrogen
O2
N2
There are
groups of
two atoms
in each
molecule.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
CREATING ELEMENTAL POETRY
The original
http://www.youtube.com/watch?v=GFIvXVMbII0
The rap
http://www.youtube.com/watch?v=pmTXtbRR7c0&f
eature=related
Everyone can do it!!!
http://www.youtube.com/watch?v=QWkVO6Bp8VM
&feature=related
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
CREATING ELEMENTAL POETRY
Use what you’ve heard and the periodic table and
textbooks to write a poem/song about
EITHER
1. an element and its properties
OR
2. a number of elements on the periodic table
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Learning Objectives
By the end of the lesson I can:
•Recall that all substances are made up of atoms
•Describe and explain what is inside an atom
•Describe how elements contain only one type of atom
•Understand that symbols are used for atoms to show what
happens in chemical reactions.
•Know that all 100 known elements are listed on the periodic
table and groups have similar properties
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Atoms and symbols
All substances are made up of p______.
articles
The smallest p_____
article that can take part in a chemical
reaction is called an a___.
tom
Elements are substances that each contain only
_______
one typeof atom. The atoms of each element are
represented by a symbol.
Examples of symbols used for elements are O (used
oxygen N (used for nitrogen
for ______),
_______) and Cu (used for
______).
copper
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
More work on symbols
Fill in the gaps in the table below.
Name of
element
Chlorine
Symbol
Cl
Carbon
C
Silver
Ag
Bromine
Br
Sodium
Na
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
How are the elements arranged?
Answer: Using the Periodic Table
Vertical columns are called
groups
___________
and
horizontal rows are called
periods
___________.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Elements, mixtures and compounds
Elements – these are substances containing only
one
type of atom For example, sodium is an
______________.
element and is made up of sodium atoms only.
Compounds – these are substances made up of
two or more types of atom. These atoms are joined
together chemically. For example, carbon dioxide
contains carbon and oxygen atoms joined together by
chemical bonds.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Mixtures – these are not pure substances.
The compounds and/or elements making them
up are not joined chemically. For example, air
is a mixture of gases like oxygen (an element)
and carbon dioxide (a compound).
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Elements, mixtures and compounds,
continued
Classify the following substances as elements, mixtures
or compounds.
mixture
compound
element
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
How do we name compounds?
The rules are:
1. If there are two elements present, then the
name ends in –IDE.
For example, the formula CuS represents
sulf
the compoundcopper
_________ide.
2. If there are three elements present and
the third one is oxygen, then the name
ends in –ATE.
For example, the formula CuSO4
represents coppersulf
_________ate.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Naming compounds, continued
Name the compounds in the table below.
Formula
AlCl3
CuO
Fe2O3
CaSO4
CaCO3
MgBr2
NaNO3
Name
Aluminium chloride
Copper oxide
Iron oxide
Calcium sulfate
Calcium carbonate
Magnesium bromide
Sodium nitrate
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Chemical reactions
The substances that react are called the
REACTANTS.
The substances formed are called the
PRODUCTS.
REACTANTS
PRODUCTS
To represent chemical reactions we write
word equations or symbol equations.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Chemical reactions, continued
Write word equations for the following reactions
1 When sodium is burned in oxygen, sodium
oxide is formed.
sodium(s) + oxygen(g)
sodium oxide(s)
2 When solid calcium carbonate is heated, it
decomposes into solid calcium oxide and
carbon dioxide gas.
carbon
heat calcium
Calcium carbonate(s)
oxide(s) + dioxide(g)
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Does the mass change during a chemical reaction?
NO
The answer to this is ___.
For example, when 56 g of iron reacts with 32 g of
sulfur iron sulfide is formed. The mass of the iron
88 g.
sulfide formed is __
When 48 g of magnesium is heated in oxygen, 80 g
of magnesium oxide is formed. What mass of
oxygen is needed to react with the magnesium?
The answer is __
32 g.
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
Burning fossil fuels
The three fossil fuels are:
Coal, oil and natural gas.
When the fossil fuels are burned in enough air they
always form water and carbon dioxide. Carbon
lobal
dioxide is a __________
greenhouse gas and is linked to g____
w______.
arming
Write the word equation for methane (natural gas)
burning in oxygen.
methane(g) + oxygen(g)
carbon dioxide(g) + water(l)
GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element.
The Reactivity Series
Metals are arranged in order of how reactive they
are. A more reactive metal will displace a less
reactive one from its compounds.
For example, zinc will displace copper from copper
sulfate to give zinc sulfate plus copper. The word
equation is:
zinc(s) + copper sulfate(aq)
zinc sulfate(aq) + copper
GCSE Core Chemistry