year 9 modules student work teaching resources

Modules 17 & 18 - Atoms, Elements, Compound & Mixtures

Modules 17 & 18 - Atoms, Elements, Compounds and Mixtures - Revision

Here are the key ideas from Modules 17 & 18 . Make sure that you also look at your written notes and the sites on the links page.

Elements, Mixtures & Compounds

ELEMENTS are the simplest substances in nature.

All of the elements are shown in a table called the PERIODIC TABLE. In this table they are grouped so that elements which behave in similar ways are in the same group.

Every element in the periodic table is given a SYMBOL (e.g. Fe is iron, Cu is copper, O is oxygen)

The smallest part of an element is called an ATOM

An element contains only ONE TYPE of atom - e.g. the element coppper contains only copper atoms, the element oxygen conttains only oxygen atoms and so on.

A COMPOUND contains two or more elements chemically bonded together.

A MIXTURE contains different elements or compounds mixed together (not bonded together)

This piece of apparatus is called a LIEBIG CONDENSER. It is used for DISTILLATION. Can you remember how it works?

Separating Mixtures

MIXTURES can be separated in different ways:

1. A mixture of two liquids can be separated by DISTILLATION

2. A mixture of a liquid and an INSOLUBLE solid can be separated by FILTERING

3. A solid can be separated from a solution by EVAPORATING off the liquid

4. A mixture of dyes can be separated using CHROMATOGRAPHY. The mixture is placed onto chromatography paper and water is used to separate the dyes.

Metals and Non-Metals

METALS usually have the following properties:

They are HARD
They are MALLEABLE (can be bent into shape)
They CONDUCT HEAT and ELECTRICITY well
They are sometimes MAGNETIC (iron, nickel, cobalt)
They are SONOROUS when hit (ring like a bell)

NON- METALS usually have the following properties:

They are BRITTLE (break apart when struck or bent)
They DO NOT CONDUCT HEAT and ELECTRICITY well
They are NOT MAGNETIC

POTASSIUM SODIUM CALCIUM MAGNESIUM ZINC IRON COPPER SILVER GOLD
The reactivity series

The Reactivity Series

Different metals are more or less reactive than each other. We can order the metals by reactivity from the most reactive to the least reactive. We call this order the REACTIVITY SERIES:

We can test the reactivity of metals in two ways:

1. See how quickly they react with acid or oxygen (by burning them in air)
2. Set up contests between pairs of metals for other elements. A more reactive metal is able to displace (kick out) a less reactive metal from a compound. We call these reactions DISPLACEMENT REACTIONS.

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