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1. Slide 1: Science Interactive LTD Copyright 2005 Science Interactive LTD Science base multimedia CD-ROM for PC is a collection of 38 units or tools totalling over 1150 PowerPoint slides. Each unit covers a wide range of different delivery and learning styles, offering an exciting way to involve your pupils during lessons or revision sessions. All styles of teaching and learning are supported through use of high quality images, graphics, challenging exercises and questions. Units can be used in the classroom via an interactive whiteboard, data projector or used during individual study via a PC or school network. Science Interactive LTD. PO BOX 50764 LONDON NW6 9AT email: sales@science-interactive.co.uk web: www:science-interactive.co.uk Unit 1: The Digestive System Unit 20: Crude Oil and its Products Unit 2: The Circulatory System Unit 21: Rock Cycle Unit 3: Healthy Body and Immunity Unit 22: Elements, Molecules and Compounds Unit 4: The Respiratory System Unit 23: Ionic and Covalent Compounds Unit 5: Nervous System and the Senses Unit 24: The Halogens, their Uses and Compounds Unit 6: Human Homeostasis Unit 25: The Noble Gases, their Properties and Uses Unit 7: Hormones and the Endocrine System Unit 26: Rates of Reaction Unit 8: Drugs and Bad Body Maintenance Unit 27: Energy Unit 9: Photosynthesis in Green Plants Unit 28: Generating Electricity and its Domestic Use Unit 10: Water Transport in Plants Unit 29: Electricity Unit 11: Flow of Energy and Elements through the Environment Unit 30: Light and the Electromagnetic Spectrum Unit 12: Mitosis and Meiosis Unit 31: Radioactivity Unit 13: Inheritance and Selection Unit 32: Newton's Forces and the Effects of Forces Unit 14: Evolution and Human Impact Unit 33: Earth and Space Unit 15: Genetic Engineering Unit 34: The Earth and Plate Tectonics Unit 16: The Periodic Table and its Elements Unit 35: The Alkaline Earth Metals Unit 17: The Alkali Metals Unit 36: Sound and Hearing Unit 18: Metals and their Properties Unit 37: Natural Forces Unit 19: The Transitional Metals Unit 38: Cells, Tissue, Organs and Organs systems
2. Slide 2: Science Interactive LTD Copyright 2005 Unit 23  Ionic and Covalent Compounds 
3. Slide 3: Unit 23: Ionic and Covalent Compounds Science Interactive LTD Copyright 2005 Understand: Keywords: Ionic, Covalent, Compounds, Metals, Non What are everyday materials made from. 1. metals, Ions, Bonds, Physical, Chemical, The differences between an element, molecule 2. Properties, Reactions, Atoms, Bond, and compound. Molecules, Giant, Covalent & Structures. That atoms of different elements can either be 3. joined together by ionic or covalent bonds. That ionic compounds include a metal and at 4. least one non metal element. The physical and chemical properties of ionic 5. compounds. How to represent ionic compounds by ‘dot and 6. cross’ diagrams. That covalent compounds contain only non 7. metal atoms. The physical and chemical properties of covalent 8. compounds. That covalent compounds can exist as simple 9. molecules or giant covalent structures. 10. How to represent covalent compounds by ‘dot and cross’ diagrams. Click mouse to begin Science Interactive LTD PO BOX 50764 LONDON NW6 9AT web: www.science-interactive.co.uk email: sales@science-interactive.co.uk
4. Slide 4: Science Interactive LTD Copyright 2005 The periodic table Elements in the periodic table are arranged by their atomic number, which is determined by the number of protons each element contains. Using this rule gives rise to groups of e_________ with similar chemical and physical properties. There are eight distinct groups of elements, for example group one elements are the reactive alkaline metals. There are also 30 elements known as the transitional metals. There are five periods or r______. Each element has its own unique symbol which is used all over the World to save time. Find the symbols for the following elements: Sodium, Gold, Iron, Oxygen, Nitrogen and Neon ? The periodic table: Word bank: elements rows The periodic table (Look at the metallic, non metallic and semi metallic elements) Describing elements Each element has its own The Alkaline Metals H He symbol, atomic number and The Alkaline Earth Metals 1 2 Metals atomic mass. The symbol for Semi Metallic Elements I II III IV V VI VII VIII each element is unique. This Non-Metals Li Be B C N O F Ne is not always the first letter The Halogens 3 4 5 6 7 8 9 10 The Noble Gases of the element. Na Mg Al Si P S Cl Ar 12 11 13 14 15 16 17 18 K Ca Kr Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br 19 20 36 12 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Atomic mass Rb Sr Xe Mo Y Zr Nb Tc Ru Rh Pd Ag Cd In S Sb Te I C 37 38 Symbol 42 54 39 40 41 43 44 45 46 47 48 49 50 51 52 53 Cs Ba Hg La Hf Ta W Re Os Ir Pt Au Ti Pb Bi Po At Rn Atomic number 6 55 56 80 57 72 73 74 75 76 77 78 79 81 82 83 84 85 86 Fr Ra 87 88 There are over 100 elements in the periodic table. There are eight groups, the transitional metals and five periods or rows in the periodic table. Each vertical group of elements have very similar chemical and physical properties because of their similar electronic configuration (electrons in shells)
5. Slide 5: Science Interactive LTD Copyright 2005 Understanding materials one All materials, compounds or chemicals are made from matter. All matter is made from atoms of elements. There are just over 100 elements in the periodic table that combine together in different ways to give rise to all the different types of m__________ that we use and see every day. There are four main groups of materials: 1:Elements 2:Metal alloys 3:Ionic Compounds 4:Covalent Compounds Elements, metallic alloys and compounds: Word bank: materials Elements Metal alloys Ionic compounds Covalent compounds Diagram Notes There are over a 100 An alloy is a mixture of Ionic compounds like Covalent compounds like elements which join two or more different salt contain metal and methane contain non- together to form over 30 metals. Bronze is an non-metal elements. Salt metal elements only million compounds or alloy and is used in is very important to Methane or natural gas is materials: coins and statues. humans. a fossil fuel: Diamond contains one Bronze contains copper Salt contains sodium and Methane contains type of atom Carbon and tin chlorine. Carbon and hydrogen
6. Slide 6: Science Interactive LTD Copyright 2005 Understanding materials two Each element has an internationally recognised s_______ and unique atomic and mass number. Atoms of different elements like sodium (reactive group I metal) and chlorine (reactive group VII non metal gas) are all made from three identical sub atomic particles. Elements are made from electrons, protons and neutrons. The only difference between elements is the number of each sub atomic particle. Therefore, the number of electrons, protons and neutrons each element contains determines all their physical and chemical properties. What makes a reactive metal like sodium, simply 11 electrons and protons and 12 neutrons. What makes a reactive g____ like chlorine, simply 17 electrons and protons and 20 neutrons and that’s it !! Elements in the periodic table: Word bank: symbol gas Mercury Gold Oxygen Sulphur Diagram Particle diagram Notes Mercury atoms Gold atoms Oxygen molecules Sulphur atoms
7. Slide 7: Science Interactive LTD Copyright 2005 Understanding materials three Most of the elements in the periodic table are m_______, but what about the non metals. Some are solids like carbon and sulphur, some are liquid like bromine, but most are gases like nitrogen, oxygen and chlorine. C________ is found in all fuels and biological molecules. Many of the gaseous elements are found in our atmosphere, for example oxygen which is essential for respiration and combustion of compounds containing carbon. The halogens including chlorine and iodine all have antiseptic properties. The Noble gases which includes helium are a family of un-reactive gases. Are there any exceptions to these general properties for non metals ? Non metals in the periodic table: Word bank: metals carbon Element Carbon (Diamond) Carbon (Graphite) Hydrogen Neon Diagram Notes Notes Carbon atoms Carbon atoms Hydrogen molecules Neon atoms
8. Slide 8: Science Interactive LTD Copyright 2005 Understanding materials four Each element in the periodic table has its own very different properties. Metals and non-metals have very different uses and p__________. Metals like copper, aluminium, zinc and iron are hard, shiny, dense, malleable, ductile, conductive of heat and electricity. Non-metals like carbon and sulphur usually have the opposite properties. They are d_____, soft, brittle and poor conductors of heat and electricity. Are there any exceptions to these general properties for metals ? Metals in the periodic table: Word bank: properties dull Iron Aluminium Lithium Gold Iron is used to build Aluminium with its high Lithium is an extremely Gold has a high monetary complex machines and strength to weight ratio soft and reactive metal. value and is used to make super structures like the is used in planes and Although it cannot be used jewellery. Governments French Eiffel tower. bike frames. It is also a like iron or copper it is use gold to guarantee Corrosion can be a safe material to store used in batteries like the their paper currencies. problem. fizzy drinks. one pictured here.
9. Slide 9: Science Interactive LTD Copyright 2005 Understanding metal alloys Metals in their pure form are often not as useful as metal alloys. Alloys are mixtures of different m________ that give an alloy its useful and unique properties. In iron, all the atoms are the same, because iron is an element. In a metal alloy like steel, all the atoms are not the same. Steel contains iron atoms, carbon atoms and other metals atoms like chromium and nickel. Iron the pure element, is like any other metal, but it rusts combining readily with o________ and water. Steel which does not rust is also much stronger. That’s why we use the majority of iron for making steel. What is a metal alloy and give two examples ? Materials and what they contain: Word bank: metals oxygen Bronze alloys Steel alloys Aluminium alloys Titanium alloys Diagram Bronze is an alloy first Steel is stronger and Planes contain millions Bike frames are made Notes made over 2000 years more rust resistant than of moving parts but are from titanium alloys ago and is used in iron because it also made largely of because it is an extremely coins and statues. contains the elements: lightweight metals like: strong and light material. Bronze contains Iron, Carbon, Zinc & Aluminium, Magnesium, Contains titanium & copper and tin. Chromium. Zinc & Titanium. Aluminium
10. Slide 10: Science Interactive LTD Copyright 2005 Compounds one Atoms of elements rarely exist in their pure form, because atoms of elements like to transfer, gain or share electrons during the formation of stable compounds. Apart from g_____, nitrogen and the noble gases, most elements are joined to other elements in compounds. A compound contains two or more different types of elements joined together by a chemical bond. These c__________ can either be ionic or covalent. Compounds always have a formula which tells us the type and number of atoms they contain. Ionic and covalent compounds: Word bank: gold compounds Sand Water Sodium Chloride Calcium Carbonate SiO2 H2O NaCl CaCO3
11. Slide 11: Science Interactive LTD Copyright 2005 Compounds two Apart from the Noble gases (Helium, Neon, Argon & Krypton), all elements have partially filled outer electron shells. The Noble gases are very un-reactive because they have f_____ shells. Other elements would also like to have full shells or the same electronic configuration as the Noble gases. They can do this by either losing, gaining or sharing e_________ with other elements when they form compounds. Ionic and covalent compounds: Word bank: full electrons Sand Water Sodium Chloride Calcium Carbonate O O H H H H H H SiO2 H2O NaCl CaCO3 H 2+ _ H +H 2+ 2- O 2- H C 2+ Ca Si H H O O Na H H Cl C H O Ca Mg OO S O C O H H O O H C O O
12. Slide 12: Science Interactive LTD Copyright 2005 Ions and Ionic compounds Metals react with non-metals to form ionic compounds. The formation of an ionic bond involves the transfer of electrons from metal elements to non metal elements. Metals have usually just one or two e_________ in their outer shell. During the reaction, these outer electrons are t__________ from the metal atom to the non metal atom forming ions. Metals form positively charged ions and non-metals form negatively charged ions. After the reaction, both metal and non metal ions have the electronic configuration of the Noble gases. They are said to be stable. Name five ionic compounds of the metal magnesium? Formation of metal and non metal ions: Mg O Word bank: electrons transferred Atom Ion Noble gas configuration Magnesium - + 2- 2+ 2+ 2- Na Cl O Ne O O Mg Mg Mg Mg O Oxygen 2- 2+ 2- 2- Ne Ne O Mg Mg O Mg O O Mg
13. Slide 13: Science Interactive LTD Copyright 2005 Reactions forming Ionic compounds Metals atoms want to lose electrons whilst non metal atoms want to gain electrons. They do this to become like Noble gases having a full o_______ shell. When electrons are transferred from metals to non metals during a c__________ reaction, the ions are oppositely charged. These oppositely charged ions attract each other very strongly, for example the melting point of many ionic compounds is usually very high. What sort of ions does oxygen, chlorine and fluorine form ...Explain your answer ? Formation of sodium chloride: Word bank: outer chemical Sodium and chlorine atoms Electron transfer Sodium chloride - + Na Cl Na Cl Na Cl Ionic bond Sodium atoms have one During the chemical Ions of sodium and chlorine electron in their outer shell. reaction, the electron from are formed which are both very Chlorine atoms have seven sodium is transferred from stable. The charged ions attract electron in their outer shell. sodium’s outer shell to the one another in an ionic bond. Both are unstable atoms. chlorine atom. Both atoms These are electrostatic forces Explain why ? form ions of atoms. of attraction.
14. Slide 14: Science Interactive LTD Copyright 2005 Building ionic crystals Ions of atoms build crystals. The structure extends itself in all directions, giving the crystal a regular arrangement of ions called a lattice. For sodium chloride, the ions arrange themselves alternatively in all three d___________. This gives sodium chloride crystals a cubic shape. All ionic solids have similar ionic structures to sodium chloride. Did you know you can grow your own crystals using a small seed crystal and a saturated ionic solution...it takes about a week ! Ionic crystals: Word bank: dimensions Sodium chloride Simple unit Crystal structure Diagram - + 2+ 2- Cl- Cl- Na Cl O Mg Na+ Cl- Cl- Diagram Sodium chloride: Ions of sodium and chlorine have opposite charges. Simple unit: The attraction between the sodium ion and the chloride ions form a single unit. Ions begin to build three dimensional shapes in a regular shape. Crystal structure: Thousands of ions arrange alternatively to form salt crystals.
15. Slide 15: Science Interactive LTD Copyright 2005 Ions of metals All reactive metals found in group I, II and III lose electrons to form positive ions of atoms. Metals lose e__________ from their outer shell to other non metal atoms during a chemical reaction. When they lose their outer electrons they adopt the same electronic configuration as the N______ gases. They are said to be stable. Look at the table below and discover the simple rules for group I, II & III metals. Metal ions in ionic compounds: Word bank: electrons noble Group one (all lose one electron) Group two (all lose two electrons) Group three (all lose three electrons) Group Li Atom Lithium Magnesium Aluminium 2- + + Al Li O Li Mg Mg Li Li -+ Magnesium + 3+ 3+ Ion Lithium ion 2+ 2- ion Aluminium ion Na Cl O Mg Li Li Al Al Al Al Ne
16. Slide 16: Science Interactive LTD Copyright 2005 Ions of non metals All reactive non-metals found in group VII, VI and V gain electrons to form negative ions of atoms. Non-metals gain electrons in their outer shell from other metal atoms during a chemical reaction. When they gain their outer electrons, they adopt the same electronic configuration as the Noble gases. Also they are said to be s_______. Look at the table below and discover the simple rules for group VII, VI & V non metals. Non metal ions in ionic compounds: Word bank: stable Group seven (all gain one electron) Group six (all gain two electrons) Group five (all gain three electrons) Grou H S C p - - Nitrogen - Fluorine Atom Sulphur O F S S F N N F S F S S F SS F N N N H H Fluoride ion Sulphide ion Nitride ion Ion - - 3- 2- 3- 2- 2- S S F S S F N N F S S F N N S S S S
17. Slide 17: Science Interactive LTD Copyright 2005 Properties of ionic compounds Ionic compounds, based on the chemistry of their ionic bond have certain physical and chemical properties. Mostly, they are highly soluble in water and have a crystalline structure under the m__________. Ionic compounds of the transitional metals like copper and titanium are highly coloured. They also conduct electricity when molten or in solution. They also have very high m_________ points. Magnesium oxide for example, lines the inside of pottery kilns that operate at very high temperatures (2000oC) List five ionic compounds and their uses, for example sodium chloride ? Properties of ionic compounds: Word bank: microscope melting Property one Property two Property three Property four Property five Chlorine gas Anode NaCl Molten Molten Sodium Sodium Cathode Property one: Some ionic compounds are very coloured. Most ionic compounds of group I and II metals are white in colour. Property two: They form regular crystals and appear like mini diamonds under the microscope. Property three: They have very high melting and boiling points due to the very strong forces of attraction between the ions. Property four: When molten or in ionic solutions, ionic compounds can conduct electricity. Property five: They are usually highly soluble in water.
18. Slide 18: Science Interactive LTD Copyright 2005 General rules for ionic compounds There are several rules that help you to understand what happens to the a_____ and their electrons during the formation of ionic compounds. Remember for atoms to be stable they either need to lose of gain electrons to empty or fill their outer shells, therefore having the same electronic configuration as the Noble gases. Ions of atoms are very stable and once formed do not easily revert back to their a________ electronic configuration. That’s why we have so many compounds and very few elements found in their natural state. Ionic compounds and their rules: Word bank: atoms atomic Rule one Rule two Rule three Rule four and five - + Na Cl Na Cl Cl Na Ionic Bond Rule One: Ionic compounds contains a metal and non-metal. Rule two: Metals always lose electron (s) forming a positively charged ions. Rule three: Non-metals always gain these electron (s) forming negatively charged ions. Rule four: The attraction between the positive and negative ions is the ionic bond Rule five: The overall charge of an ionic compound must always equal zero.
19. Slide 19: Science Interactive LTD Copyright 2005 Dot and cross diagrams Dot and cross diagrams help up understand what has happened to the electrons of atoms of metals and non-metals involved in a chemical reaction. Dot and cross diagrams also show the c________ of an ion of an element. Rules: One: Show outer shells only Two: Always show charges of ions outside square brackets Three: Always place ions in square brackets Four: Showing more than one ion: Place them in brackets with a number outside it. Five: Always place a symbol for the element. Six: The overall charge on a compound should always be zero Word bank: charge Example one Example two Compound Aluminium fluoride (AlF3) Sodium Oxide (Na2O) + Al 3+ Aluminium Ion Na+ Sodium ion Metal ion F- Fluoride ion O 2- Oxide ion Non-metal ion Li Li Dot and cross AlF3 Na2O - 2- + 3+ - 2- Mg O Na N Cl O Al SAl Mg F S F N Mg x2 x3
20. Slide 20: Science Interactive LTD Copyright 2005 Covalent bonding Non metals can also react with other non metal atoms to form covalent compounds. The formation of covalent compounds involves the sharing of electrons between non-metal atoms. During the reaction, non metal atoms fill their outer shells by sharing electrons from other non metal atoms. They are said to be stable. The shared electrons form the c_________ bond which holds together the atoms in molecules. We find covalent bonding of atoms, in simple molecules to complex c__________. Name five compounds or molecules that contain a covalent bond ? O O H H H H Formation of covalent compounds: O O H H H HH H H H Word bank: covalent compounds Atoms (Hydrogen & Oxygen) Electron sharing Water (H2O) H O O H H H O H C H OS O O O O H C O OS O SH O OH H H H H H H H H H Both oxygen and hydrogen HDuring the chemical Because electrons are shared, each atom O H C H atoms have incomplete outer reaction, the electrons pair in the water molecule is stable. Water is S shells. O Both elements H are up and are shared by the slightly polar and has the ability to H H O unstable. Oxygen can form H to up Coxygen and H hydrogen dissolve solutes like salt. It is a very H two single Hcovalent bonds with atoms. This sharing is called important molecule, essential for life on CO HO O O H H two hydrogen atoms. C the covalent bond. Earth. O O O O S O H H H
21. Slide 21: O O Science Interactive LTD Copyright 2005 Reactions forming covalent compounds H H H H Although non-metal atoms can gain electrons to fill their outer shell during the formation of ionic compounds, they can also share their electrons with other non-metal atoms forming covalent molecules. Electrons s_______ between atoms hold both atoms together, and for example in H diamond and silica.....these covalent bonds are extremely strong. There are many examples of s________ covalent molecules which have very different properties. What sort of ions does O H C H oxygen, chlorine and fluorine form ... Explain your answer ? O S O H H H Formation of methane: O O H H OH HO Word bank: shared simple H H H Atoms (Hydrogen & Carbon) Electron Sharing Methane (CH4) H O O H H H O O O O OH H C H C H C S O S O H H O O H H H H H H H O During theHchemical reaction, the C H Both hydrogen and carbon atoms Because electrons are shared, each S O have incomplete H outer shells. electrons pair up Hand are shared atom in the methane molecule is H Both elements are unstable. by O the carbon Hand hydrogen stable. Carbon has the ability to O O Carbon can form up to four atoms. This sharing is called Othe build veryOlong chains like proteins C O O single covalent bonds with four covalent bond. Methane has four and the organic fuels known as the H C H C S O hydrogen atoms. H covalent bonds. alkanes. H H
22. Slide 22: Science Interactive LTD Copyright 2005 Single, double and triple covalent bonds There exists three types of covalent bonds: single, double and triple bonds. Single bonds occur between two atoms sharing a single pair of electrons. Double bonds occur between atoms that share two pairs of electrons and triple bonds occur between two atoms that share three pairs of electrons. Atoms joined together by a triple covalent bond are very difficult to s__________, for example the nitrogen molecule is very un-reactive because both nitrogen atoms are joined by a triple covalent bond. Single, double or triple bonds: Word bank: separate Single (Methane) Double (Oxygen) Triple (Nitrogen) O O H CH4 O2 N2 H C H N N O O H H H H H H A single covalent bond like that A double covalent bond like that H A triple covalent bond like that found in methane contains two found in oxygen contains four found in nitrogen contains six shared electrons. shared electrons. shared electrons. O H C H O O O
23. Slide 23: Science Interactive LTD Copyright 2005 Covalent molecules one In some elements like nitrogen and oxygen, the atoms pair up. A particle that consists of more than one atom is called a m_________. All the group VII halogens, Fluorine, Chlorine, Bromine and Iodine also pair up in molecules. We can show how many atoms that a molecule contains by using a formula. Oxygen, for example consists of t____ oxygen atoms with the formula O2. Nitrogen has also two nitrogen atoms with a formula N2. Write down the formula of fluorine, chlorine, bromine & iodine ? Simple covalent molecules one Word bank: molecule two Oxygen Nitrogen Hydrogen Ozone Diagram N N N2 H2 O3 O2 Oxygen found in our Nitrogen is found in our Hydrogen is not found Ozone is made from three Notes atmosphere is used atmosphere and makes on its own. It is bound atoms of oxygen and is during respiration by up nearly 79% of it. It is to other elements in found in the top layers of all cells. Oxygen is inert in this form but in compounds like water. our atmosphere. Without produced by green nitrates it is absorbed and Hydrogen is also the ozone, UV light would plants during photo- used by plants to build fuel of our own Sun in prevent all life from synthesis. proteins. the solar system. surviving.
24. Slide 24: Science Interactive LTD Copyright 2005 Covalent molecules two Molecules containing more than one type of atom are the building blocks of all compounds. In a compound, the atoms of different elements are chemically bonded together. Water for example, is a compound made up from two elements; hydrogen and oxygen. We can represent how many a______ of each element and how they are joined to each other using a chemical formula or a p_________ diagram. Ammonia the compound, has a formula NH3. This tells us that a single ammonia molecule contains three atoms of hydrogen joined to one atom of nitrogen. Simple covalent molecules two Word bank: atoms particle Hydrochloric acid Water Ammonia Methane Sulphur dioxide Diagram H20 NH3 CH4 S02 HCl HCl is used in Water is called Ammonia is made Methane, a fossil Sulphur dioxide is Notes laboratories and is and known as the during the Haber fuel is removed emitted as a also found in the molecule of life. industrial process from underneath pollutant during stomach. The HCl It is essential for and is an important the rock. Methane the combustion of acid helps protein all life to exist starting compound is combusted with fossil fuels like digestion. here on Earth. for fertilisers. oxygen. petrol.
25. Slide 25: Science Interactive LTD Copyright 2005 Properties of simple covalent compounds Covalent compounds, based on the chemistry of the covalent bond, have certain properties. Mostly, they are colourless, have extremely low melting and boiling points. They also do not conduct electricity Covalent compounds containing carbon form long c_______ like proteins and polyethene. A huge number of compounds exist as s_______ covalent molecules and include water (H20) oxygen (O2) and all organic molecules for example methane (CH4) and octane (C5H12) Covalent bonding is also found in the molecule of life DNA ! Properties of simple covalent compounds: Word bank: chains small Property one Property two Property three Property four H H H H boiling point melting point O O S O H H Property one: They all have simple molecular formulas: CH4 H2O Cl2 NO2 CO CO2. Property two: Contain only non metal elements and they do not conduct electricity. Property three: Have relatively low melting and boiling points and are usually quite reactive. Property four: Fill their outer electron shell by sharing electrons with other atoms of non metal elements.
26. Slide 26: Science Interactive LTD Copyright 2005 Giant covalent molecules one Carbon is a relatively unique element. Carbon can build giant covalent structures by sharing electrons. In these structures, every carbon atom is joined to the next carbon atom by a very strong covalent bond. Giant covalent structures have very different p__________ when compared to simple covalent molecules. They are very hard and have high melting and boiling points. For example, there exists three forms or allotropes of c________: Diamond, Graphite and Buckminster Fullerene. Explain why diamond is the hardest substance on Earth ? Allotropes of carbon: Word bank: properties carbon Buckminster fullerene Diamond Graphite Diamond is the hardest known Graphite conducts electricity, Buckminster fullerene can trap natural substance. Each atom is held allowing electrons to flow between molecules inside is 3D sphere. It can in place by 3 other carbon atoms. its layers. Used a an un-reactive also be stretched into fibres to make Highly expensive, valued for its conductor of electricity. Used also in modern composite materials called rarity and refraction of light. Costs pencils for writing. The soft layers are carbon fibre. They are used in tennis up to £4,000 per carat weight. left on the paper. rackets, bike frames and F1 cars.
27. Slide 27: Science Interactive LTD Copyright 2005 General rules of covalent compounds Dot and cross diagrams help up understand what has happened to the electrons of non metal atoms involved in a chemical r_________ producing covalent compounds. Dot and cross diagrams show how electrons are shared by atoms. Rules: One: Covalent molecules contain non-metal atoms. Two: Atoms fill their outer shell by sharing electrons with other atoms. Three: Shared electron pair (s) form the covalent bond joining atoms together. Four: Make sure that each atoms has a full shell. H H H H Five: Always place a symbol for the element. General rules of covalent compounds: Word bank: reaction Example one Example two Compound Ethene (C2H4) Ammonium (NH3) Carbon (Group 4...needsO electrons to fill shell) 4 Nitrogen (Group 5...needs 3 electrons to fill shell) O O S O H H Hydrogen (Group 1...needs 1 electron to fill shell) Hydrogen (Group 1...needs 1 electron to fill shell) C2H4 NH3 Dot and cross H H N C C H H O H H H
28. Slide 28: Science Interactive LTD Copyright 2005 Summary of the behaviour of elements The table below gives a summary of the behaviour of atoms found in the eight different g_______ in the periodic table. All metals form positive ions and all non-metals form negative ions. Only non metals form covalent compounds. Only the Noble gases (group 8) do not participate in chemical reactions because they are stable with full shells. Li Li Li H H H He He He Ne Ne H H N N N Summary of the behaviour of elements: Word bank: groups Group I Group II Group III Group IV Group V Group VI Group VII Group VIII O Li B B B Ne C C FN C OH F Be He Ne O B Be Be Be Valence=1 -3 Valence = 2 Valence = 3 Valence 4 +1 +1 5 Valence Valence = 6 -3 Valence = 7 Valence = 8 -3 -3 Ionic Ionic Ionic Ionic Ionic Ionic O None Li Li H Ne H HH He He NeH He O NN N N H H [ion] C [ion] +2 [ion] +3 [ion] -3 [ion] -2 [ion] +1 -1 F O B F Be Covalent Covalent Covalent Covalent None 4 shared bond 3 shared bond 2 Shared bond 1 shared bond H H y nlO C Ne H N H C H +2 -3 +1 +1 +3 +3 +1 -2 +1 -1 -2 -1 -2 -1 -2 o S O nt e alNeC C B Li H He H N O Li O B B HF O F O Be Be Be Be le Ov ab Co O H H H H St H ly ly ly N on on on H F O B O O H O H H H C H le H H H H O O O ic ic ic O S O +3 b H +1 -1 -2 a on on on St H H I I I F O B C Be C
29. Slide 29: Science Interactive LTD Copyright 2005 Extension questions and homework 1: Define the following terms: Atom, Molecule, Compound, Element, Material, Alloy, Ionic & Covalent. 2: Complete the table: A B C D E Pure element of only _______________ _________________ _______________ ________________ one type of atom ______________? ________________? ______________? _______________? 3: a) Give three examples of each of the following; Elements, Single molecules and compounds b) Based on their physical properties answer the following.: Why is gold metal use for rings and necklaces. Why is iron used to build bridges and other structures like buildings. c) The chemical formula of carbon dioxide is CO2, of sugar C6H12O6 what does this tell you about both molecules and the elements present. d) Work out the relative atomic mass (Ar) or relative formula mass (Mr) of the following: CaCO3, Al2O3, NaOH, H2, C4H10 & C12H24, CuSO4, CO, H20, Fe2O3, O3, O2, H2O2 + SO2 (RAM H = 1, C = 12, O = 16, Na = 23, Al = 27, S = 32 & Ca = 40) 4. Complete the table. Element Symbol Ar & RAM Protons Neutrons Electrons 23 Na Na 11 12 11 Sodium 11 Al 27 Al Aluminium 13 U 92 143 92 Uranium
30. Slide 30: Science Interactive LTD Copyright 2005 5: Answer the following: a) What are the differences between ionic and covalent bonds. b) Describe the 3 ways in which atoms of elements can be joined together in a substance. c) (i) Do metals gain or lose electrons (ii) Do non-metals gain or lose electrons. d) If an atom gains an electron what charge will the ion have. e) If an atom loses an electron what charge will the ion have. f (i) What charge will you find on a group 2 ion (ii) What charge will you find on a group 6 ion. g) Draw a dot cross diagram to show what happens when a lithium atom reacts with a chlorine atom. Name the compound formed and give its relative formula mass. 6: Using the table below, answer the following: SO42- Mg2+ O2- Kr MgO CO2 C2H4 H2O C6H12O6 O2 a) From the ions atoms and molecules above choose. b) An example of a gas containing single atoms. c) An example of a substance made from ions of atoms. d) An example of a non-metal ion. e) An example of a metal ion. f) An example of a complex ion. g) An example of a simple covalent gas molecule. h) An example of a liquid covalent molecule. 7: Answer the following: a) Sodium chloride is held together by strong ionic bonds. What is the nature of these bonds and why are they so strong. b) Why does a solution of sodium chloride conduct electricity, but solid sodium chloride is not able to. c) Give the correct formulas of the following ionic compounds. d) Draw dot and cross diagrams to show the bonding in each ionic compound. KF, Li2O Na2S & ALF3
31. Slide 31: Science Interactive LTD Copyright 2005 8: Complete the table for the following compounds: Substance Formula Structure Substance Formula Structure Graphite Sea water Giant covalent structure Solid metallic element Diamond Silver Water H20 Molten MgCl2 Sodium chloride Bronze Ammonia NH3 Dissolved CuSO4 9: Answer the following questions: a) What are the general properties of ionic and covalent compounds. b) What are the differences between simple covalent molecules and giant covalent structures. Give 2 examples. c) Draw dot and cross diagrams for the following covalent compounds. HCL, NH3 CCl4 PF3 N2. d) Atoms usually want 8 electrons in their outer shell to be stable. Explain why hydrogen only requires two electrons in a covalent bond for example H2. e) (i) Give the relative formulae for the following; Aluminium iodide, Aluminium oxide, Water, Decane, Ethane, Carbon dioxide , Calcium carbonate, Carbon monoxide, Copper Nitrate, Copper Oxide, Ethene and Glucose. (ii) State whether these compounds are ionic or covalent. 10: Complete the following simple equations: a) Sodium + Chorine _________ __________ b) Carbon + __________ Carbon dioxide c) 2Li + __________ Li2O Internet: Go to google.co.uk and find out about the electrolysis of bauxite during the manufacture of aluminium. In addition find out about the 3 forms of carbon, their properties and uses; Diamond, Graphite and C60 or Buckminster Fullerene.