卤素 第七主族.doc

双语文件 化学（07级双语）Chemistry (07 Bilingual)教 案Teaching Plan姓名董坤化学学院College of ChemistryPrimary Department Subject chemistry Class 3 Grade 3Preparing Time 45min Date 2010 .06 .13 By 董坤 NAME OF LESSONChapter 12.1 Group(AS)POINTS OF EMPHASISPhysical and chemical properties of Group.POINTS OF DIFFICULTY(1) Chemical properties of Group,especially displacement reactions.(2) The rules change with increasing atomic numbers.AIMSKnowledge and Technology: (1) Understand and explain the physical and chemical properties of Group,especially chlorine,bromine and iodine.(2) Describe the relative reactivity of the elements Cl2, Br2 and I2 in displacement reactions and explain this trend in terms of oxidising power,i.e. the relative ease with which an electron can be captured.(3)Describe and explain the reactions of the elements with hydrogen.Process and Method: The students will be able to understand the rules with increasing atomic numbers and develop the capability of observation.Emotional attitudes and views: (1) Stimulate students interest in learning chemistry. (2) Through the study of properties of Group,develop their self-learning ability.NEW WORDSHalogen卤素 derived源于 Greek希腊语 term术语 pale苍白 greenish绿 crystalline透明的 sublimes升华 purple紫色 vapour蒸气 isotopes同系物 radioactive放射性 deepen加深 outermost shell最外层 general formula通式 halide卤化物 hypohalous次卤化物MATERIALSMultimedia computer, test book of A-LEVELPREPARATIONPowerPointPROCEDURESActivity 1(minutes)Teacher Hello my dear friends!Students Hello teacher.Teacher OK. Before our class begins. I want to introduce a famous person named Lu Su,who worked for Sun Quan as a strategist in Eastern Han.He was dead at the age of 46.In this lesson we will meet a new name .Its pronunciation is familiar with its chemical name in Chinese.Its halogens.Chinese mean of halogen is Lu Su ,too.They have seem pronunciation but stand for different things.Its a new name for us,so read after me please!Halogen!Halogen!Students Halogen, Halogen!Teacher The name halogen is derived from the Greek and means salt producing. It was first used to the beginning of the nineteenth century because chlorine,bromine and iodine are all found in the sea as salts.Nowadays we still use the term.The elements of Group are called the halogens,so the topic today is Group.Writing on the blackboard Chapter 12.1 GroupTeacher Look at a part of periodic table of the elements.How many elements are in Group?Who can tell me?You please!Students Five.Teacher Good job!There are five elements in Group.What are they?Students (answer question)They are fluorine, chlorine, bromine, iodine and astatine.TeacherOK. Look screen now please! Read after me. Fluorine, chlorine, bromine, iodine, astatine!Activity 2(minutes)Teacher Fluorine, chlorine, bromine, iodine, astatine!Teacher OK.From the table of Group,we can know their atomic number increase.So how will their physical properties and chemical properties change with increasing atomic numbers?Lets learn the first part: physical properties of Group.Writing on the blackboard .Physical propertiesTeacher I will give you five pictures.Now look at these pictures and who can tell me their physical properties with increasing atomic numbers?You please!Writing on the blackboard a.With increasing atomic numbersStudents First picture is a pale yellow gas,it is fluorine.Chlorine is a greenish yellow gas/Bromine ,dark red liquid/Iodine is purple.Astatine is a dark solid.Teacher Well done!I will give you right answers.Fluorine is a pale yellow gas.Chlorine is a greenish yellow gas.Bromine is a dark red liquid giving off a dense red vapour.Iodine is a shiny,grey-black crystalline solid which sublimes(changes directly from a solid to a gas)to a purple vapour.Astatine is a solid,too.All the isotopes are radioactive and so this element will not considered here.So according my introduction,we can know two points about physical properties with increase atomic number of Group. What are they?StudentsColour change/States from gas to solid.Teacher OK!Very good!With increasing atomic numbers the colour deepens and States from gas to solid.Writing on the blackboard i.the colour deepens. ii.States from gas to solid.Next ,lets analysis the table please.What are they?Students Melting point and boiling points.Teacher How their melting points change?Students melting points increase.Teacher What about boiling points?Students Increase,too!Teacher OK,good job!They are all increase with increasing atomic numbers.Writing on the blackboard iii.melting points increase.iv.boiling points increase.Teacher According these pictures we can know their densities increase,too!Writing on the blackboard v.densities increase.TeacherThe halogens are a family of non-metallic elements.So they are non-metals .Writing on the blackboard b.they are non-metals.Teacher OK. So much for the physical properties of Group.Please look at the screen. According to their atomic structures we can know there are 7 electrons in the outermost shell.As a result ,the most common oxidation state for the halogen is negative one(-1).We shall not include fluorine in all the discussions,because its small size and high electro-negativity give it some special properties.The second part,we will learn chemical properties of Group .Writing on the blackboard .Chemical propertiesTeacher Halogens react with hydrogen to give the corresponding hydrogen halide.Now I will write down an equation on the blackboard.Writing on the blackboard a.react with H2 Cl2 + H2 2HClActivity 3(minute)Teacher Next I will ask you to come here and write down another equations .Any volunteers?You please!Students (hands up!)Writing on the blackboard Br2 + H2 2HBr , I2 + H2 2HI.Teacher Another students write down on your note book, and I will check your answers later.If you have any questions,hand up please!(several time later)Thank you very much!Go back to your sit please!Is he/she right?Students Yes!Teacher Good job!You are right(big hands)! You can check your answers on the screen.From these three equations,we can know the general formula!Writing on the blackboard X2 + H2 2HXTeacher Halogens react with water to give the corresponding hydrogen halide and hypohalous acid.Now I will write down an equation on the blackboard.Writing on the blackboard b.react with H2O Cl2 + H2O HCl + HClOTeacher Next I will ask you to come here and write down another equations .Any volunteers?You please!Students (hands up!)Writing on the blackboard Br2 + H2O HBr + HBrO I2 + H2O HI + HIOTeacher Another students write down on your note book please! If you have any questions,hand up please! I will check your answers now!(several time later)Thank you very much!Go back to your sit please!Is he/she right?Students Yes!Teacher Good job!You are right(big hands)!From these three equations,we can know the general formula! Who can right down the general formula? You please!Students (hands up!)Writing on the blackboard X2 + H2O HX + HXOTeacher Thank you! Is he/she right?Students Yes!Teacher You did a good job(big hands)!You can check your all answers on the screen.Next we will learn displacement reactions among chlorine,bromine and iodine.It is very important in this class.I hope everyone can remember the regular clearly!Can you ?Students Yes,I can!Teacher OK,I will give you the rules about displacement reactions among halogens!Chlorine displalces bromine and iodine.Bromine displaces iodine. Iodine dose not displace either chlorine or bromine.I will right down the left of the equation about chlorine displaces bromine.Writing on the blackboard c.displacement reactions Cl2 +Br- TeacherAccording to my introductions,Who can come here and right down them?Any volunteers?Students Cl2 + Br- Cl- + Br2Teacher Is he/she right?Students No/Yes!Teacher Yes or no?Yes?Students No!Teacher We must remember atomic number equal in order to keep the equation balance.So there are two bromide ions join this reaction and two chloride ions produced in this equation.The right answer is Cl2 + 2Br- 2Cl- + Br2.Are you clear?Students Yes!Writing on the blackboard Cl2 + 2Br- 2Cl- + Br2Teacher Next I will ask you come here and help me with complement another equation. Any volunteers? You please!Writing on the blackboard Cl2 + 2I- 2Cl- + I2 Br2 + 2I- 2Br- + I2Teacher Thank you! Is he/she right?Students Yes!Teacher Well done (big hands)!From these three equations,we can analysis their elements oxidizability and ionic reducibility.Who can tell me the elements oxidizability?Students Elements oxidizability:Cl2 Br2 I2.Teacher Thank you! Is he/she right?Students Yes!Writing on the blackboard Elements oxidizability:Cl2Br2I2Teacher How about ionic reducibility?Students Ionic reducibility: I-Br-Cl-.Teacher You are very clever! Oxidizability of elements is on the left more than right. Ionic reducibility is negative.Are you remember them?Students Yes!Writing on the blackboard Ionic reducibility: I-Br-Cl-Teacher So much for our lesson.Well learn more about the chemical properties in next lesson and learn them more detail. Now lets review this lesson. Today we have learnt the physical and chemical properties of Group .Their color deepens,states,melting and boiling points,densities are all increase with increasing atomic numbers. Ionic reducibility