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A basic powerpoint
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Objectives
• Know how to name compounds
• Know how to write formulas
• Know how to work out how many of each atom there are in a compound, based on a formula
Compounds contain two or more different types of atom.
Atoms in compounds
The compound, water, exists as molecules.
Each water molecule consists of two hydrogen atoms joined to one oxygen atom.
Water is produced from the chemical reaction between hydrogen and oxygen.
Making a compound – water
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?
Properties of a compound –
carbon dioxideA compound has different properties to the elements from which it is made because the atoms are joined differently.
+ O OC
Black solid used as
fuel.
Colourless gas in which many
substances burn.
Colourless gas used in fizzy
drinks and fire extinguishers.
+
carbon oxygen carbon dioxide+
Copper Element Mercury Element
Aluminium Element Oxygen Element
Water (H2O)
Iron sulphide (FeS)
Carbon dioxide (CO2)
To name simple compounds of metals and non-metals:
Naming simple compounds
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
What is the name of each compound formed by these metal and non-metal elements?
nitrogenlithium
sulphurzinciodinenickel
brominealuminium
oxygentin
chlorinesodiumnitrogenmagnesium
sulphuriron
Name of compoundElement2Element 1
iron sulphidemagnesium nitridesodium chloridetin oxide
aluminium bromidenickel
iodidezinc sulphidelithium nitride
Naming simple compounds
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 nitratecopper sulphatealuminium
bromate
Naming further compounds
For compounds containing two elements plus oxygen, the ending of the other non-metal usually changes to “--ate”.
A compound always contains a particular amount of each element. It has a fixed composition.
Composition of compoundsA 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?
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.
Writing a formula
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. 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?
What is the formula?
TiO2
Li2O
AlCl3
(In a formula put the metal first as when naming a compound.)
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?
What is the formula?
SiCl4
MnO2
Al2O3
(In a formula put the metal first as when naming a compound.)
What is the ratio of atoms?
What does a formula show?