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1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Some new symbols to get used to…
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Key words; Atom, Compound, Electron, Element, Symbol
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
How do you know?
H H
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•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
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Atoms and symbols
All substances are made up of p______. The smallest p_____ that can take part in a chemical reaction is called an a___.
Elements are substances that each contain only _______ of atom. The atoms of each element are represented by a symbol.
Examples of symbols used for elements are O (used for ______), N (used for _______) and Cu (used for ______).
articlesarticle
tom
one type
oxygen nitrogen
copper
1 of 20 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.
Sodium
Bromine
Ag
C
Chlorine
SymbolName of element
Cl
Carbon
Silver
Br
Na
1 of 20 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
___________ and
horizontal rows are called
___________.
groups
periods
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Elements, mixtures and compounds
Elements – these are substances containing only ______________. 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.
one type of atom
1 of 20 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).
1 of 20 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
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•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
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Key words; Atom, Compound, Electron, Element, Symbol
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•Understand that symbols are used for atoms to show what happens in chemical reactions.
•Know that atoms bond and rearrange in a chemical reaction
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
A compound is made when atoms of different elements react and join together.
For example, water is produced from the chemical reaction between hydrogen and oxygen.
Two hydrogen molecules react with one oxygen molecule to produce two molecules of water.
+H H
H HO O
hydrogen oxygen water+
Why does water have different properties to its elements?
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
A compound has different properties to the elements from A compound has different properties to the elements from which it is made because the atoms are joined differently.which it is made because the atoms are joined differently.
Black solid used as fuel.
Colourless gas in which many
substances burn.
Colourless gas used in fizzy drinks and fire extinguishers.
+
+ O OC
carbon oxygen carbon dioxide+
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
A compound is not a mixture
The atoms in water, the compound made when hydrogen and oxygen react and their atoms become chemically joined to each other, look like this…
The atoms in a mixture of hydrogen gas and oxygen gas, which have not reacted with each other, look like this…
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
To name simple compounds of metals and non-metals:
2. Write down the name of the non-metal, changing the ending of the word to “-ide”.
1. Write down the name of the metal.
What is the name of the compound made when the following elements combine?
magnesium and oxygen
sodium and chlorine
oxygen and iron
magnesium oxide
sodium chloride
iron oxide
1 of 20 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 the compound _________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 _________ate.
copper sulf
copper sulf
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
What is the name of each compound formed by these metal and non-metal elements?
nitrogenlithium
sulphurzinc
iodinenickel
brominealuminium
oxygentin
chlorinesodium
nitrogenmagnesium
sulphuriron
Name of compoundElement 2Element 1
iron sulphide
magnesium nitride
sodium chloride
tin oxide
aluminium bromide
nickel iodide
zinc sulphide
lithium nitride
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Many compounds contain more than two elements.
oxygenbrominealuminium
oxygensulphurcopper
oxygen
oxygen
oxygen
Element 3
nitrogensodium
magnesium nitratenitrogenmagnesium
nickel sulphatesulphurnickel
Name of compoundElement 2Element 1
sodium nitrate
copper sulphate
aluminium bromate
For compounds containing two elements plus oxygen, the ending of the other non-metal usually changes to “--ate”.
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Naming compounds, continued
Name the compounds in the table below.
Formula Name
AlCl3CuO
Fe2O3
CaSO4
CaCO3
MgBr2
NaNO3
Aluminium chloride
Copper oxide
Iron oxide
Calcium sulfate
Calcium carbonate
Magnesium bromide
Sodium nitrate
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
A compound always contains a particular amount of each element. It has a fixed composition.
Composition of compounds
A compound contains atoms from different elements that are chemically joined together.
Compound names can get quite long and complicated, so the symbols of the elements are used as a shorthand.
The symbols of the elements in a compound are combined to give the formula of the compound.
What is the formula of carbon dioxide?
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
carbon dioxide
A formula uses the symbols of the elements in a compound.
When there is more than one atom of each element, the number is always written after the symbol.
carbon atom = 1formula =
hydrogen atoms = 2formula =
The formula shows the ratio of atoms in a compound.
water
CO2
H2O
oxygen atoms = 2
oxygen atom = 1
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1. Titanium oxideFor every titanium atom there are two oxygen atoms.Formula =
2. Lithium oxide For every two lithium atoms there is one oxygen atom.
Formula =
3. Aluminium chloride For every aluminium atom there are three chlorine atoms.
Formula =
What is the formula of each of these compounds?
TiO2
Li2O
AlCl3
(In a formula put the metal first as when naming a compound.)
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1. Silicon chlorideFor every silicon atom there are four chlorine atoms.Formula =
2. Manganese oxide For every manganese atom there are two oxygen atoms.
Formula =
3. Aluminium oxide For every two aluminium atoms there are three oxygen atoms.
Formula =
What is the formula of each of these compounds?
SiCl4
MnO2
Al2O3
(In a formula put the metal first as when naming a compound.)
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•Understand that symbols are used for atoms to show what happens in chemical reactions.
•Know that atoms bond and rearrange in a chemical reaction
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•Understand that symbols are used for atoms to show what happens in chemical reactions.
•Know that atoms bond and rearrange in a chemical reaction
•Work safely in the lab to make compounds from elements
1 of 20 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.
To represent chemical reactions we write word equations or symbol equations.
REACTANTS PRODUCTS
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
A word equation can be used to describe any chemical reaction, i.e. any process in which atoms become joined in different ways.
The steps for writing a word equation are:
1. On the right-handside, put the name of the reactant(s).If there are two or more reactants, link them with a + + sign.
2. In the middle, write down an arrow ().
3. On the right-handside, put the name of the product(s). If there are two or more products, link them with a + + sign.
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
The lead and oxygen don’t mix, they react to form lead oxide. This means that the lead and oxygen atoms in the product are joined differently to the atoms in the reactants .
Lead reacts with oxygen to form lead oxide.
lead + oxygen lead oxide
Why is lead oxide so different to both lead and oxygen?
What is the word equation for this reaction?
1 of 20 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.
Calcium carbonate(s)calcium oxide(s)
heat carbon dioxide(g)+
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1. Limestone (calcium carbonate) is heated to make calcium oxide and carbon dioxide.
2. Magnesium reacts with hydrochloric acid to make magnesium chloride and hydrogen.
3. Methane is burnt to make carbon dioxide and water.
calcium carbonate calcium oxide +carbon dioxide
magnesium + hydrochloric acid magnesium chloride + hydrogen
methane + oxygen carbon dioxide + water
Write out word equations for the following chemical reactions.
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Investigation: For each of the following;
• Burn magnesium
• Pour hydrochloric acid over magnesium
• Pour sulphuric acid over zinc
1. Complete the experiment & write an observationWrite a word equationWrite a symbol equationBalance the equationDescribe the ratio of atoms in the compound composition of the products
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1) When calcium carbonate burns it turns…..(complete the experiment & write an observation)
calcium carbonate calcium oxide +carbon dioxide2) complete the word equation
3) CaCO3(s) CaO(s) + CO2(g) complete the symbol equation4) 1 Ca 1 Ca
1 C 1 C3 O 3 O balance the equation
5) 1 Calcium atom to every 1 oxygen atom AND 1 carbon atom to every 2 oxygen atoms. describe the ratio of atoms in the compound composition of the products
6) complete diagrams of at least one of the equations
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Does the mass change during a chemical reaction?
The answer to this is ___.NO
For example, when 56 g of iron reacts with 32 g of sulfur iron sulfide is formed. The mass of the iron sulfide formed is __ g.88
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 __ g. 32
1 of 20 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 dioxide is a __________ gas and is linked to g____ w______.
greenhouse lobalarming
Write the word equation for methane (natural gas) burning in oxygen.
methane(g) + oxygen(g) carbon dioxide(g) + water(l)
1 of 20 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
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
Learning Objectives
By the end of the lesson I can:
•Understand that symbols are used for atoms to show what happens in chemical reactions.
•Know that atoms bond and rearrange in a chemical reaction
•Work safely in the lab to make compounds from elements
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element
1 of 20 GCSE Core Chemistry
Exam tip; A symbol represents 1 atom of an element