Atoms Elements and Compounds

1. Atoms Elements and Compounds

2. Atoms and Elements • Everything is made up of tiny particles called atoms • Atoms are tiny the tiniest speck you can see contains millions of atoms! • Molecular Expressions: Science, Optics and You - Secret Worlds: The Universe Within - Interactive Java Tutorial

3. Elements • When a substance is made of only 1 type of atom it is called an element • For example Copper is only made of Copper atoms it can’t be broken into anything simpler

4. The periodic Table of elements • This is a table of all the types of elements found on earth • Anything that exists is either one of these elements or a mixture of them! • Element Song • Do you recognise any of these elements?

5. Definitions • An atom is the smallest part of an element that still has the properties of that element • An Element is a substance that cannot be broken down into simpler substances by chemical means

6. Some common elements • Carbon – A solid that can have 2 forms, grey graphite or pencil “lead” or the gemstone Diamond! It is not a metal

7. Sulfur - a yellow solid non metal, it makes matches and gunpowder

8. ery • Iron – A hard silvery grey solid metallic element it is very common and is used to make ships, cars, skyscrapers etc.

9. Silver – a bright grey solid metal used to make jewellery and ornaments

10. Gold – A heavy, precious yellow metallic element, used for jewellry

11. Sodium – A soft, silver white metallic element that is very reactive! It is used in street lighting as it glows yellow when burned

12. Symbols of Elements • Each element has its own chemical symbol, usually it is the initial of the element eg, H for Hydrogen, but sometimes the symbols come from Latin eg. Na for Sodium • The first letter is always a capital • The second letter if there is one is always a small letter

14. Compounds • There are only about 100 elements but we know there are hundreds of thousands of other substances such a s salt, water, plastic, carbon dioxide , sand etc. • These substances are made of 1 or more elements chemically combined together • Water is H2O this means Hydrogen and Oxygen chemically combined together

15. Definition • A compound is made when two or more elements combine together chemically

16. Making a compound • If we burn 2 elements such as iron and sulphur together we can get a completely new substance called Iron Sulphide • Look at the properties of iron and sulphur before they are chemically combined

17. If the iron and sulphur are mixed together the iron can be separated using a magnet • When they are chemically combined the iron is no longer magnetic! • A compound is a completely new substance with its own properties

18. Think of Water • Water is made of Hydrogen which is an explosive gas and oxygen which is needed to burn things yet when they combine to form H2O you get a liquid that can put out fires!

19. Molecules • A compound is made up of molecules • 1 H2O is a molecule of water • Carbon Dioxide gas is CO2 what type of atoms are in a molecule of Carbon Dioxide? • Answer

20. Big Molecules • Some molecules are very big and contain lots of atoms • A molecule of sugar is C12H22O11 • This means that 1 molecule of sugar has 12 carbons, 22 hydrogens and 11 oxygens!

21. Small Molecules • Some molecules are very small Hydrogen gas is made of H2 molecules which is 2 hydrogen atoms

22. Definition • A molecule is the smallest part of an element or compound that can exist on its own

23. Fixed amounts • The atoms that make a compound are present in definite fixed amounts • For example water will always have 2 hydrogens and one oxygen in a molecule • Salt NaCl will always have one sodium and one Chlorine in a molecule