1) Elements are pure substances that cannot be broken down further by chemical processes. They are represented by chemical symbols on the periodic table. 2) Compounds are pure substances composed of two or more elements chemically bonded together in a fixed ratio. Their properties are different from the original elements. 3) Mixtures are physical combinations of two or more substances that are not chemically bonded and can be separated by physical means like filtration or distillation. Their properties are similar to the original substances.

1. Elements, Compounds & Mixtures

2. Matter Elements Compounds Mixtures

3. Elements A pure substance that cannot be decomposed into two or more simpler substances by chemical processes or electricity

5. Elements Match the symbols to their elements. Cl Arsenic Na Sulfur Mg Chlorine As Magnesium S Sodium

7. Elements Made up of particles known as atoms

8. Elements Atoms are the smallest particles of an element chemical properties of that element

12. Quiz Which of the following are representations of compounds? O H H O C C N N

13. Compounds

14. Compounds A pure substance that Contains 2 or more elements Chemically combined S eparated by chemical means

15. Compounds P roperties are different from its parent elements

16. Compounds Since compounds are chemically combined, their formation involves an E nergy change

17. Compounds C omposed of different elements combined in a fixed ratio Hydrogen + Oxygen  Water 2 Hydrogen + 1 Oxygen  1 Water

19. Compounds Guess the elements present Sulfur dioxide Silver nitrate Iron(II) sulfate Nitrogen dioxide Magnesium chloride

20. Compounds Elements are represented by symbols Compounds are represented by chemical formula

22. Chemical Formula of Compounds Rules: 4) Carbon Dioxide, C O 2 4) Oxygen is usually written at the end (except for hydroxide) 3) Water, H 2 O not H 2 O 1 3) Need not write subscript ‘1’ 2) Magnesium Carbonate, MgCO 3 2) Number of atoms is written on the right of the symbol 1) Calcium Oxide, Ca O 1) Metallic element is written first

23. Compounds Compounds can decompose into simpler substances when heat is applied Thermal Decomposition

24. Mixtures Two or more substances Added together Without chemical bonds being formed Impure Substances

25. Mixtures Can be made up of; Elements + Elements Alloys Elements + Compounds Air Compounds + Compounds Our Body

26. Mixtures S eparated by physical means Chromatography Filtration Distillation Crystallization

27. Mixtures P roperties are same as its parent elements or compounds

28. Mixtures Since no chemical bonds are formed, formation of mixtures involves No E nergy change

29. Mixtures C omposed of different substances combined in a variable composition Composition of air: 20% O 2 , 79% N 2, 1% other gases Not Fixed!

30. Alloys Mixture of metals with other elements Stronger than pure metals Eg: steel (Fe + C) brass (Cu + Zn) solder (Pb + Sn)