Metals and Non Metals

1. Metals and Non Metals

3. Metals Good conductors of heat and electricity. They are all solids at room temperature except mercury. Most of them can be hammered into different shapes (malleable) and drawn into wires (ductile). Metals have a shiny appearance.

4. Group 1 Alkali Metals • soft metals • cut with a knife to give a shiny surface. • have low density – Li, Na, K float on water. • very reactive metals & stored under paraffin oil. • reactivity increases down the group. • alkali metals react vigorously with water to give hydroxides and hydrogen.

5. Group 1 Alkali Metals • Lithium is used in batteries since they are powerful and lightweight • Sodium is used in street lamps and nuclear reactors • Potassium is essential for the healthy growth of plants

6. Group 2 Alkaline Earth Metals • harder metals. • have higher density compared to Group 1. • less reactive than Group 1. • reactivity increases down the group. • they react with oxygen when heated to give the oxides.

7. Group 2 Alkaline Earth Metals • Magnesium is used in rescue flares and fireworks. • Calcium carbonate is present in limestone, marble or chalk. • Barium sulphate which is insoluble is used in barium meals. A patient takes it so that their digestive system will show up on X-ray.

8. Transition Metals • less reactive than Group 1 and 2. • hard and dense. • good conductors of heat and electricity. • High mpts, bpts (very strong metallic bond) • have coloured ions except for zinc.

9. Non Metals Poor conductors of electricity and heat. Usually have low melting points (11 of them are gases and 1 is a liquid at room temperature). Brittle Dull appearance.

10. Group 7 Halogens • low mpts & bpts. • fluorine is a pale yellow green gas • chlorine is a greenish- yellow gas bromine is dark red orange liquid • iodine is dark grey crystalline solid.

11. Group 7 Halogens • Fluorine is the most reactive of all non-metals • Teflon is a fluorine compound used in non-stick lining on pans Most toothpaste contain fluoride to prevent tooth decay

12. Group 7 Halogens • Chlorine: kills bacteria in swimming pools • Bromine is used in pesticides and to make medicine. • Iodine is an antiseptic.

13. Group O Noble gases • colourless gases. • exists as separate atoms. • found in the Earth’s atmosphere. • have low mpts and bpts .

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15. Group O Noble gases • Helium is used in air ships. • Argon is used in light bulbs. It won’t react with the tungsten filament. • Neon glows red in low pressure tubes when high voltage is applied. • Krypton is used in lasers to repair the retina behind the eye.

16. Isotopes Look at the following chlorine atoms 3517Cl 3717Cl What is the difference between them?

17. Isotopes 3517Cl 3717Cl Electrons 17 17 Protons 17 17 Neutrons 35 – 17 = 18 37 – 17 = 20

18. Isotopes Therefore, isotopes are atoms of the same element with the same number of protons but different number of neutrons

19. Page 65 Isotope Protons Neutrons Electrons 126 C 146 C 6 6 6 6 8 6

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22. C H Class work Page 68 Carbon atom Hydrogen atom

23. Class work Na F Sodium atom Fluorine atom

24. Question 6 The statements below are about metals and non-metals. Circle which is true or false All metals conduct electricity. True All metals are solid at room temperature. False Non-metals are good conductors of electricity. False Non-metals are solids, liquids or gases at room temperature. True Most metals are brittle and break when hammered. False Most metals are ductile. True There are many more metals than non-metals in the periodic table True

25. Question 7 The element Boron exists as 2 different isotopes. 10 5B 11 5B Natural Boron contains about: 20% Boron – 10 and 80% Boron – 11 What are isotopes? Atoms of the same element having same number of protons but different number of neutrons. Using the two isotopes of Boron as an example explain how the atoms are different from each other. Boron-10 has 5 protons and electrons and neutrons, Boron-11 has 5 protons and electrons but 6 neutrons.

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