1 / 59

METALLIC BONDING

METALLIC BONDING. Büşra AÇIKEL Gamze KARACA Azize ŞEN. Lesson Plan. Grade level : 10 th grade Unit Number : 3 Unit : Chemical Species and Their Interactions Topic : Metallic Bonding Allocated time: 2 x 45 hours = 90 minutes. Learning Outcomes.

jolie
Download Presentation

METALLIC BONDING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. METALLIC BONDING Büşra AÇIKEL Gamze KARACA Azize ŞEN

  2. Lesson Plan • Grade level: 10thgrade • UnitNumber: 3 • Unit: ChemicalSpeciesandTheirInteractions • Topic: MetallicBonding • Allocated time: 2 x 45 hours = 90 minutes

  3. Learning Outcomes • Explains the formation of metallic bonding. • Make connections between the structure of metallic bonding and the properties of metals.

  4. Prerequisities • The structure of atomic model (Valence electrons) • Chemical species ( metal, nonmetal) • Delocalized electrons • The mechanism of bonding (Ionic bonding)

  5. Concept List • electrostaticattractions • sea of electron • metallicbond • alloys • malleability • ductility • electricalconductivity • thermalconductivity

  6. Materials Needed • 10 – 15 balloons • Experiment: beher glass, silverplate, copperplate, ironplate, iceand hot water • videosandanimations

  7. 1ST LECTURE HOUR ( 45 min.)

  8. INITIATION ( 7 min.)

  9. Entrance • Greeting • Because balloons take the student’s attention we preferred to start with a student activity before reminding previous lesson • Attendance while making student activity to prevent time consuming

  10. Balloon Activity

  11. Balloon Activity( 5 min.) • Before explaining the aim of the activity, let us explaining the activity in order to make it meaningful for you in understanding our aim. • Balloonactivity: • Givestudentsinflatedballoons. • Each of thestudents is an atom of some metal.(e.g. gold) • Each of theballoon is an electronbelongingtothat atom. • Eachstudenttosses her/his electronfreelyfromhandtohandintotheairandgentlyhitsotherelectronsthatare in theair, muchlike a volleyballgamewithmanyballoonsbeingusedinstead of oneball. • Everybodywantstoplaywiththeballoons, sothiskeepstheatomstogether.

  12. Aim of the Student Activity • This activity will serve as an analogy for metallic bonding • At the end of the first lecture students will make connection between metallic bonding and the balloon activity.

  13. During Activity • While giving balloons to students, they probably wonder why teacher let them playing with balloons and so, teacher says: “ We will make a connection between our topic and this activity at the end of the lecture.” • During the activity teacher won’t make any extra explanation about the aim of this activity

  14. The Topic • After finishing the activity, teacher says: “ We know how metal and nonmetal come together, we learned how nonmetal and nonmetal come together; what about metal and metal?” • Theaimof this question is not really asking students to explain their ideas but just informing students about what will they learn in this lecture roughly.

  15. MAIN BODY ( 30 min.)

  16. Review of the last lesson(10 min.) • Afterinformingstudentsaboutthetopic, teacherstartswithreview of thelastlesson • Aim: remindingionicbondingforms a basisforbetterunderstanding of metalicbonding. Becausecomparingmetallicbondingwith a type of bondingthatstudentsarefamiliarwithprovidesstudentswithmakingconnectionsbetweennewandoldknowledge.

  17. Review of the last lesson(10 min.) • Teacher says “Let’s remember what the ionic bonding is first to understand metallic bonding better.” • Teacher asks “ Do you remember how does ionic bond form?” Expectation: We expect students to remember: • metal~ nonmetal • “e-” transfer because of octet rule • “+” and “-” ion formation

  18. Review of the last lesson(10 min.) • If students can not remember, teacher asks some guiding questions: • metal~ nonmetal: “ Between which kinds does ionic bonding formation occurs?” • octet rule/ “e-” transfer  “+” and “-” charges: “We know that elements are found as their most stable forms in the nature. For example O is seen in the form of O2. So, do you remember how an element become more stable?”(sharing/ transfer of e- (*) )

  19. Video: Ionic Bonding • After taking students respond, teacher says: “ Let’s see a video simulation showing the formation of ionic bonding.” • Video (Ionic Bonding) • Teacher makes explanation while showing video.

  20. Ionic Bonding --> Metallic Bonding • As you know metals are tend to give their valence electron instead of taking more electron So, they tend to be “+” charged. • Teacher asks: “ How do you think that metals and metals form a bond?” “ How do they look like?”

  21. STUDENTS’ MISCONCEPTIONABOUT METALLIC BONDING

  22. MISCONCEPTIONS ABOUT THE STRUCTURE OF METALLIC BONDING • Cations without mobile electrons • Unique motion of atoms with their corresponding electrons( atoms and their corresponding electrons move together such that its electrons move only in a certain place) • In metal the electron are covalently bonded (Taber 2003) • Metals have bonding similar to ionic because there is positive and negatives (Taber 2003) • There is no bonding in pure metals (Taber 2001)

  23. “Whyatoms of metals do not repeleachotherwhileallarepositivelycharged? / How can atoms of metalsstaytogetherwhiletheyarepositivelycharged?” IONIC BONDING METALLIC BONDING

  24. Possible Students’ Predictions Teacher writes the predictions on the board: • It can’t be possible • They can stay together via attraction • They can stay together with the help of electrons

  25. Sea of Electron • 00.00 – 00.27 ( Sea of Electron) • Strong side: We preferred this animation because it was the only simulation that shows the movement of both electrons and cations • Weak side: It is not clear whether the electrons are valence electrons or both inner and outer electrons

  26. Teacher Explanation • an array of metal cations in a "sea" of valence electrons

  27. Teacher Explanation • The electrons are confined to the metal by electrostatic attractions to the cations, and they are uniformly distributed throughout the structure

  28. Teacher Explanation • The valence electrons are mobile, and no individual valence electron is confined to any particular metal ion

  29. Alloys • Teacher says “We learned the structure of metallic bonding within metal” “Can we form a substance composed of two different metals?” Expectation: We don’t expect students to give detailed explanation. But some students will probably heard about alloys before from daily life.

  30. Alloys • Teacher says: “Have you ever heard about bronze medal from olympiads?” Expectation: Students probably say yes.

  31. Alloys • Coin • Steel (Iron- Manganese and some other elements) • Brass( Copper- Zinc) • Pewter ( Lead- Tin)

  32. Alloys • “These are called as alloys and alloys are mixture composed of at least 2 different metals.” • All ingredient substance are melted separately then mixed while they are liquid in certain amounts. • When they get cooler they become homogenous solid.

  33. CLOSURE ( 8 min.)

  34. Analogy (Baloon Activity) • Aim: • Providingstudentswith a chance of explainingthemetallicbondingwiththeirownwords. • Toassessstudents’ level of understandingwithinthelesson. • At theend of thefirstlecture, teacherasksstudentsto define thesimilaritiesbetweenmetallicbondingandthisactivity.

  35. Analogy (Baloon Activity) • Teacherasks: “How can wemakeconnectionbetweenmetallicbondingandbaloonactivity in thelight of thingsthatwelearned?” Expectation: • We expect students to explain that they represent some atoms of metal • We expect students to explain that balloons represent electrons belonging that atoms • We expect students to explain that moving balloons resemble the sea of electron in the metallic bonding.

  36. Analogy (Baloon Activity) • If students are not able to see the similarities between metallic bonding and balloon activity we will ask more guiding and specific questions: “What may balloons represent in the balloon activity in terms of metallic bonding?” “What may students represent in the balloon activity in terms of metallic bonding?”

  37. 2ND LECTURE HOUR ( 45 min.)

  38. INITIATION ( 5 min)

  39. The Topic • Teacher says: “ We learned the structure of metallic bonding.” “ So, What can be the properties of metals regarding of the structure of metallic bonding?” Expectation: The aim of this question is informing students about the topic of the lesson.

  40. MAIN BODY ( 30 min.)

  41. Malleability • 03.42 – 05.10 ( Metallic Bonding youtube) garipkonusanadam

  42. Malleability • As you see the atoms were shifting, did not break apart. • “Why would it that be the case?” • Because the delocalized electrons are always there. • Any shifting positively ions are going to be hold together by attraction to the constant presence of those valence electrons that sea of electrons • Delocalized electrons: Electrons belonging to certain molecules are not attached to a particular atom or bond in that molecule. These electrons are said to be "delocalized" because they do not have a specific location (are not localized)

  43. Malleability • Teacher asks: “ In where this property can be used in daily life?” Expectation: We expect students to give some examples of malleability from daily life because there are numerous examples from …. To a very complicated piece of an electronic mechanism.

  44. Malleability

  45. Ductility • Teacher asks: “What about a wire?” Expectation: Students will again probably think that it is because of malleability. • Teacher says: “ But can we get a wire by applying compressive force on a metal?” “ What other kind of force can be applied on a metal to get a wire?” Expectation: We don’t expect students to answer these questions. We just want make them thinking on. • Teacher says: “ Let’s watch a video to find answers of these questions.”

  46. Video • 01.04 – 03.46 • Aim: Teaching ductility by comparing the malleability and ductility of a metal at particular level. • Strong side: It explains malleability and ductility at particular level. • Weak side: Sea of electrons are not represented at the mean while applying force

  47. Ductility • Ductility is a solid material’s ability to deform under tensile force • After video watching, teacher asks:“ Which one the wires in the pictures represents the better ductility of a metal?”

  48. Thermal Conductivity • As a 3rd property of metals we want to teach the thermal conductivity by an experiment. • Aim: to explain thermal conductivity by comparing the thermal conductivities of three different metals Ag, Cu, and Fe. • We intentionally choose 3 different metals because we will want students to write a journal about the reason of 3 different rates of thermal conductivities.

  49. Thermal Conductivity Experiment • Activity will be done by grouping students. Each group will consist of 3-4 students. • Video of the experiment

  50. Electrical Conductivity • Teacher says: “Another property of metals is electrical conductivity.” • Video simulation • “As in the thermal conductivity, the motions of delocalized electrons conducts the electricity as well.” • “Electrical current flows easily through the moving electrons in the sea of electrons.”

More Related