资源描述
Boardworks Ltd 20071 of 352 of 35 Boardworks Ltd 2007 Boardworks Ltd 20073 of 35Where are the transition metals?The transition metals are the block of elements located between group 2 and group 3 of the periodic table.Ac Rf Db Sg Bh Hs Mt Ds RgLa Hf Ta W Re Os IrPt Au HgYZr Nb Mo Tc Ru Rh Pd Ag CdSc TiVCr Mn Fe Co Ni Cu Zn?Here,the word transition is used to mean in-between.group 2group 3 Boardworks Ltd 20074 of 35What are the transition metals?Boardworks Ltd 20075 of 35Why are they called the typical metals?There are over 30 transition metals.The transition metals are known as typical metals.Why do you think this might be?They include most of the metals we are familiar with and use everyday,such as iron,copper and gold.However,there are many transition metals that are less familiar to us,because they are very rare or have few uses.6 of 35 Boardworks Ltd 2007 Boardworks Ltd 20077 of 35The transition metals are known as typical metals because of their physical properties.They are:What are the properties of the transition metals?l lustrous(bright and shiny).l high density.l good conductors of heat and electricity.l high melting and boiling points(except mercury,which is liquid at room temperature).l hard and strong.l malleable(can be bent and pressed into different shapes)and ductile(can be drawn into wires).Boardworks Ltd 20078 of 35Transition metals and alkali metalsHow do the transition metals compare with the alkali metals?Boardworks Ltd 20079 of 35Comparing properties of different metalsHow do the properties of transition metals compare with those of alkali metals?l are more dense.This means that in a fixed volume of metal there are more atoms of a transition metal than there are of an alkali metal.l have higher melting and boiling points except mercury.l are harder and stronger.They cannot be cut with a knife.Compared to the alkali metals,the transition metals:Boardworks Ltd 200710 of 35Comparing densities of metals Boardworks Ltd 200711 of 35Comparing melting points of metals Boardworks Ltd 200712 of 35True or false?13 of 35 Boardworks Ltd 2007 Boardworks Ltd 200714 of 35How reactive are the transition metals?The transition metals are much less reactive than the alkali metals.They tend to react relatively slowly,for example with air,water and acid.Copper does not react with water whereas the alkali metals,such as sodium,react vigorously.Copper does not burn in air whereas the alkali metals,such as sodium,burn vigorously.Boardworks Ltd 200715 of 35How reactive are the transition metals?The general trend is for a decrease in reactivity from left to right across the periodic table.There are exceptions,such as zinc which is more reactive than expected.Sc TiVCr Mn Fe Co Ni Cu Zndecrease in reactivityAnother exception is iron,which does react quite readily with air and water causing rust.Zinc is more reactive than expected.What is the chemical name of rust?Boardworks Ltd 200716 of 35What happens to iron when it rusts?Rusting is an oxidation reaction between iron,oxygen and water,which leads to the formation of hydrated iron(III)oxide-the chemical name for rust.What are the word and chemical equations for the formation of rust?wateroxygenhydrated iron(III)oxide(rust)iron+4Fe(s)2H2O(g)2Fe2O3.H2O+3O2(g)+Rusting is a type of corrosion.Boardworks Ltd 200717 of 35Transition metal ionsWhen transition metals do react,they lose electrons,and so form positive ions.Some transition metals only make one type of ion,for example:However,most transition metals can form more than one type of ion,as they can lose different numbers of electrons,for example:l silver only forms Ag+ionsl zinc only forms Zn2+ions.l iron can form both Fe2+and Fe3+ions.Boardworks Ltd 200718 of 35Transition metal compoundsThe number in brackets indicates how many electrons have been lost.As most transition metals can form different ions,this means they can form multiple compounds.Copper can form Cu+,which can make the red compound copper(I)oxide Cu2O.Copper can also form Cu2+,which can make the black compound copper(II)oxide CuO.For example:Boardworks Ltd 200719 of 35Transition metal compounds and colourMost transition metals form coloured compounds.l Copper(II)sulfate crystals(CuSO4.H2O)is blue these can be turned white by heating the crystals to remove the water.l Iron(III)oxide(Fe2O3)is red/brown when hydrated this is rust.l Iron(II)oxide(FeO2)is black.For example:Boardworks Ltd 200720 of 35Uses of coloured tm compoundsThe coloured compounds of transition metals can also be used in many ways,for example:l as coloured glazes on pottery.l to colour paintsl to colour stained glass windowsThe colour of many gemstones comes from the presence of transition metal compounds.For example,the gemstone jade contains iron.Boardworks Ltd 200721 of 35How are transition metal ions identified?The presence of transition metal ions in a solution can be tested by adding sodium hydroxide solution.If transition metal ions are present,a metal hydroxide is formed.This is insoluble and so appears as a solid called a precipitate.l Cu2+ions produce a blue precipitate of Cu(OH)2.l Fe2+ions produce a grey/green precipitate of Fe(OH)2.l Fe3+ions produce an orange/brown precipitate of Fe(OH)3.Different metal ions produce different coloured precipitates:Boardworks Ltd 200722 of 35What is thermal decomposition?Compounds of transition metals can be broken down into simpler substances by heating them.For example,carbonates of transition metals are broken down into metal oxides and carbon dioxide when heated.metal oxidemetal carbonate+carbon dioxideheatHow can the presence of carbon dioxide be tested?This is called thermal decomposition.The reactants and products are different colours.The gas produced can be bubbled through limewater.If the gas is CO2,it will turn the limewater cloudy.Boardworks Ltd 200723 of 35Thermal decomposition equations+FeCO3(s)CO2(g)FeO(s)iron oxideiron(II)carbonate+carbondioxideheatThe thermal decomposition reaction of iron(II)carbonate is:What is the reaction when copper(II)carbonate undergoes thermal decomposition?+CuCO3(s)CO2(g)CuO(s)copper oxidecopper(II)carbonate+carbon dioxideheat Boardworks Ltd 200724 of 35Thermal decomposition activity Boardworks Ltd 200725 of 35Transition metals missing words26 of 35 Boardworks Ltd 2007 Boardworks Ltd 200727 of 35Spot the uses of the transition metalsHow many everyday uses of transition metals can you see?Boardworks Ltd 200728 of 35What are the uses of the transition metals?Boardworks Ltd 200729 of 35Uses of transition metals activity30 of 35 Boardworks Ltd 2007 Boardworks Ltd 200731 of 35Glossary(1/2)l alloy A mixture of a metal and at least one other element.l catalyst A substance that increases the speed of a chemical reaction without being used up.l corrosion Damage to a metal caused by a chemical or reaction such as rusting.l density A measure of mass in a given volume.Often expressed in g/dm3.l ductile The ability of metals to be drawn into wires.l lustrous Bright and shiny.l malleable Capable of being bent and pressed into a different shape.Boardworks Ltd 200732 of 35Glossary(2/2)l precipitate A solid that forms in a solution as a result of a physical or chemical reaction.l thermal decomposition The process by which a substance is broken down into two or more products by heating it.l transition metal An element located in the block between groups 2 and 3 of the periodic table.Boardworks Ltd 200733 of 35Anagrams Boardworks Ltd 200734 of 35Properties of transition metals Boardworks Ltd 200735 of 35Multiple-choice quiz
展开阅读全文