Chapter 21 Review Questions

General Chemistry: Atoms First, 2e (McMurry and Fay) Chapter 21 Metals and Solid-State Materials

21.1 Multiple Choice Questions 1) What are the most abundant minerals in the earth's crust? A) aluminosilicates and silicates B) chlorides and iodides C) nitrates and phosphates D) oxides and sulides Ans!er" A Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements 2) What minerals are important commercial sources o metals? A) aluminosilicates and silicates B) chlorides and iodides C) nitrates and phosphates D) oxides and sulides Ans!er" D Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements &) What is a principal commercial ore or the element aluminum? A) bauxite B) chalcoprite C) chromite D) hematite Ans!er" A Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements () What is a principal commercial ore or the element iron? A) cassiterite B) cinnabar C) alena D) hematite Ans!er" D Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements

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*) What is the most important copper containin ore? A) cassitrite B) chalcoprite C) chromite D) cinnabar Ans!er" B Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements +) What metal is isolated rom the ore alena? A) lead B) mananese C) tin D) ,inc Ans!er" A Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements -) What metal is isolated rom the ore sphalerite? A) copper B) mananese C) titanium D) ,inc Ans!er" D Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements ) What metal is isolated rom the ore rutile and !hat is the chemical ormula o rutile? A) aluminum/ Al20&  x20 B) mananese/ Mn02 C) tin/ $n02 D) titanium/ #i02 Ans!er" D Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements


3) What statement is inconsistent concernin the correlation o the chemical compositions o the most common ores !ith the locations o their metals in the periodic table? A) 4old and the platinum5roup metals 67u/ 0s/ 7h/ 8r/ 9d/ and 9t) are suicientl unreacti:e to occur commonl as the ree metals. B) #he earl transition metals on the let side o the d bloc; enerall occur as oxides ox ides !hile the more electroneati:e/ late transition metals on the riht side o the d bloc; occur as sulides. C) #he more electroneati:e p5bloc; metals are commonl ound as oxides and nitrates except or Al and $n !hich are ound as sulides. D) #he s5bloc; metals are ound in nature as carbon ates/ silicates and in the case o ) Which o the ollo!in metals occurs in nature principall as oxide ores? A) Ca B) Co C) Cr D) Cu Ans!er" C Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements 11) Which substance is commonl ound in nature in an uncombined orm? A) aluminum B) iron C) platinum D) tin Ans!er" C Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements 12) Which o the ollo!in elements is most li;el to occur as a metal sulide ore? A)  B)  C) = D) W Ans!er" B Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements


1&) Which o the ollo!in elements is most li;el to naturall occur as a carbonate? A) Ca B) Co C) Cr D) Cu Ans!er" A Di" 1 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements 1() What is not a metallur process? A) en:ironmental reconstruction o the landscape B) extraction o metals rom their ores C) ma;in o allos and metallic composites D) reduction o the mineral to the ree metal Ans!er" A Di" 1 #opic" #opic" $ection 21.2 Metallur 1*) Which o the ollo!in steps is not al!as necessar in the extraction o a metal rom its ore? A) chemical treatment prior to reduction B) concentration o the ore C) reduction o the mineral to the ree metal D) reinin or puriication o the metal Ans!er" A Di" 1 #opic" #opic" $ection 21.2 Metallur 1+) What is the concentration process used to separate chalcoprite 6Cue$2) rom its anue? A) chemical treatment B) densit dierences C) loatation process D) manetic dierences Ans!er" C Di" 1 #opic" #opic" $ection 21.2 Metallur 1-) o! is sla separated rom molten ore in a blast urnace? A) chemical treatment B) densit dierences C) distillation D) manetic dierences Ans!er" B Di" 1 #opic" #opic" $ection 21.2 Metallur


1) What is the name o the process commonl associated !ith the isolation and concentration o Al20& rom the ore bauxite 6Al20&  x20)? A) basic oxen process B) baer process C) contact process D) mond process Ans!er" B Di" 1 #opic" #opic" $ection 21.2 Metallur 13) #he chemical process o roastin is commonl used to acilitate the reduction o !hich metal ores? A) A/ Cu/ and  B) Al/ M/ and ) When ,inc sulide underoes roastin/ the products are A) n and $. B) n and 2$. C) n0 and $. D) n0 and $02. Ans!er" D Di" 1 #opic" #opic" $ection 21.2 Metallur 21) What is not an appropriate method o isolatin the metals sho!n? A) $6 s) s)  026 g g )  heat  6 g )  $026 g g ) B) n06 s) s)  C6 s) s)  heat  n6 g )  C06 g ) C) W0&6 s) s)  & 26 g g )  heat  W6 s) s)  & 206 g g ) D) Al20&6 s) s)  2 Cr6 s) s)  heat  Cr 20&6 s) s)  2 Al6l Al6l ) Ans!er" D Di" 1 #opic" #opic" $ection 21.2 Metallur


22) o! does one commerciall reduce the metal oxides or chlorides o sodium and manesium? A) electrolsis o the molten salts B) hih temperature reduction !ith aluminum C) hih temperature reduction !ith carbon D) roastin Ans!er" A Di" 1 #opic" #opic" $ection 21.2 Metallur 2&) Which o the ollo!in metals is not commonl obtained b electrolsis? A) Al B) i C)

2-) What conditions a:or the decomposition o G ,inc sulide? A) 1+>  B) 2&>  C) (+>  D) ++>  Ans!er" A Di" 2 #opic" #opic" $ection 21.2 Metallur 23) $teel is a mixture composed primaril o A) iron and carbon. B) iron and copper. C) iron and silicon. D) iron and sulur. Ans!er" A Di" 1 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel &>) Wh is CaC0& added to a blast urnace in the steel ma;in process? A) to i:e a source o C0 2 B) to remo:e basic oxides rom the iron ore o re C) to remo:e silicates rom the iron ore D) to remo:e unreacti:e carbon rom the iron ore Ans!er" C Di" 2 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel &1) Wh is silicon dioxide added to molten iron in the basic oxen process? A) to remo:e acidic oxides rom the molten iron B) to remo:e mananese oxide rom the molten iron C) to remo:e phosphates and carbonates carbon ates rom the molten iron D) to remo:e trace amounts o carbon rom the molten iron Ans!er" B Di" 2 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel 7 Copyright © 2014 Pearson Education, Inc.

&2) What is not a primar inredient used in the production o iron b the blast urnace process? A) co;e B) iron ore C) limestone D) phosphates and silicates Ans!er" D Di" 1 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel &&) What is not a maHor component o sla? A) Ca$i0& B) Ca&690()2 C) e20& D) Mn$i0& Ans!er" C Di" 2 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel &() 8n the reaction sho!n belo! calcium phosphate sla is ormed rom a reaction o calcium oxide !ith phosphoric anhdride. + Ca06 s) s)  9(01>6l )  2 Ca&690()26l ) Ca0 is a6n) IIIIIIII oxide/ and 9(01> is a6n) IIIIIIII oxide. A) acidic/ acidic B) acidic/ basic C) basic/ acidic D) basic/ basic Ans!er" C Di" 1 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel &*) #o three three siniicant iures/ ho! man metric tons o iron ore are needed to produce 1>/>>> metric tons o iron per da in the blast urnace process? Assume Assume that the iron ore is iron6888) oxide and that the ore is ->.>G pure. #he reaction o interest is A) 1(/&>> metric tons B) 2>/>>> metric tons C) 2>/(>> metric tons D) &>/>>> metric tons Ans!er" C Di" 2 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel

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&+) What terminolo best describes the bondin in the ollo!in schematic o a metal?

A) ionic bondin B) co:alent bondin C) electron5sea model D) crstal model Ans!er" C Di" 1 #opic" #opic" $ection 21.( Bondin in Metals &-) Which metal has maximum illin o bondin molecular orbitals and minimal illin o antibondin molecular orbitals in its composite s-d composite s-d band? band? A) Au B) Cs C) 7e D) W Ans!er" D Di" & #opic" #opic" $ection 21.( Bondin in Metals &) Which o the ollo!in is the sotest and most maleable? A) Cu B) @ C) 7u D) Mn Ans!er" A Di" & #opic" #opic" $ection 21.( Bondin in Metals &3) Which substance is the best conductor o electricit? A) diamond B) ermanium C) old D) phosphorus Ans!er" C Di" 1 #opic" #opic" $ection 21.( Bondin in Metals Alo. 0ption" alorithmic

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(>) Metals are ood conductors o heat because A) the :alence electrons are ree to mo:e about the crstal lattice. B) heat is carried as ;inetic ener b rapid :ibrations rom atom to atom in the crstal lattice. C) metal cations in the crstal are eicient at transportin heat. D) holes are created in the crstal lattice as electrons enter the conduction band and the holes conduct the heat !hile electrons conduct electrical chare. Ans!er" A Di" 2 #opic" #opic" $ection 21.( Bondin in Metals (1) Which one o the ollo!in metals is expected to ha:e the hihest meltin point? A) Cd B) Cr C)  D) n Ans!er" B Di" & #opic" #opic" $ection 21.( Bondin in Metals Alo. 0ption" alorithmic (2) %lectrical resistance o a metal IIIIIIII !ith increasin temperature. A) can decrease or increase B) decreases C) does not chane D) increases Ans!er" D Di" 1 #opic" #opic" $ection 21.( Bondin in Metals (&) What tpe o substances exhibit an increase in conducti:it !ith an increase in temperature? A) both metals and semiconductors B) onl insulators C) onl metals D) onl semiconductors Ans!er" D Di" 1 #opic" #opic" $ection 21.* $emiconductors


(() White tin has an electrical conducti:it that decreases !ith increasin temperature/ an d ra tin has an electrical conducti:it conducti:it that increases !ith increasin increasin temperature. #hereore/ !hite tin is classiied as a6n) IIIIIIII/ and ra tin is classiied as a6n) IIIIIIII. A) insulator/ metal B) metal/ insulator C) metal/ semiconductor D) semiconductor/ metal Ans!er" C Di" 1 #opic" #opic" $ection 21.* $emiconductors (*) Which o the ollo!in is a semiconductor? A) Al B) B C) 4a D) 9b Ans!er" B Di" 1 #opic" #opic" $ection 21.* $emiconductors (+) Which one o the ollo!in is an electrical insulator? A) alumina B) ermanium doped !ith antimon C) old D) tellurium Ans!er" A Di" 2 #opic" #opic" $ection 21.* $emiconductors Alo. 0ption" alorithmic (-) Which substance is a ood semiconductor? A) diamond B) ermanium C) old D) phosphorus Ans!er" B Di" 1 #opic" #opic" $ection 21.* $emiconductors () Which substance has a larer band ap than silicon? A) diamond B) copper C) ermanium D) sil:er Ans!er" A Di" 1 #opic" #opic" $ection 21.* $emiconductors 11 Copyright © 2014 Pearson Education, Inc.

(3) Which element has the larest ener band ap? A) C 6diamond) B) $i C) 4e D) $n 6!hite) Ans!er" A Di" 1 #opic" #opic" $ection 21.* $emiconductors *>) Which element has the smallest ener band ap? A) C 6diamond) B) 4e C) 9b D) $i Ans!er" C Di" 1 #opic" #opic" $ection 21.* $emiconductors Alo. 0ption" alorithmic *1) o! !ould one classi a ermanium  ermanium crstal doped !ith arsenic? A) conductor B) n5tpe semiconductor C) p5tpe semiconductor D) insulator Ans!er" B Di" 1 #opic" #opic" $ection 21.* $emiconductors *2) o! !ould one classi copper mixed !ith tin? A) conductor B) n5tpe semiconductor C) p5tpe semiconductor D) insulator Ans!er" A Di" 2 #opic" #opic" $ection 21.* $emiconductors *&) o! !ould one classi a silicon crstal doped !ith indium? A) conductor B) n5tpe semiconductor C) p5tpe semiconductor D) insulator Ans!er" C Di" 1 #opic" #opic" $ection 21.* $emiconductors 12 Copyright © 2014 Pearson Education, Inc.

*() Which one o the ollo!in is an n5tpe n 5tpe o semiconductor? A) alumina B) ermanium doped !ith antimon C) ermanium doped !ith boron D) tellurium Ans!er" B Di" 1 #opic" #opic" $ection 21.* $emiconductors **) Which one o the ollo!in is a p5tpe o semiconductor? A) ermanium doped !ith antimon B) ermanium doped !ith boron C) tellurium D) JBa2Cu&0Ans!er" B Di" 1 #opic" #opic" $ection 21.* $emiconductors *+) Which combination o semiconductors can be emploed to ma;e a diode? A) 4aAs doped !ith 4e and 4a9 doped !ith $i B) 4aAs doped !ith $e and 4a9 doped !ith n C) $i doped !ith B and 4e doped !ith 4a D) $i doped !ith 9 and 4e doped !ith As Ans!er" B Di" ( #opic" #opic" $ection 21.+ $emiconductor Applications *-) Which statement about a diode laser is false? A) iht is emitted !hen a re:erse bias is applied to the p5n Hunction. B) %lectrons and holes recombine at the p5n Hunction. C) A laser ca:it relects the emitted liht bac; and orth to pro:ide stimulated emission. D) #he liht emerin rom the laser possesses eat intensit/ a sinle reEuenc/ and a sinle phase. Ans!er" A Di" 2 #opic" #opic" $ection 21.+ $emiconductor Applications *) 9hoto:oltaic cells use liht to A) excite electrons into the conduction band b and o a n5tpe semiconductor. B) excite electrons into the conduction band b and o a p5tpe semiconductor. C) excite holes into the conduction band o a n5tpe semiconductor. D) excite electrons into the :alence band b and o a p5tpe semiconductor. Ans!er" A Di" 2 #opic" #opic" $ection 21.+ $emiconductor Applications


*3) A liht emittin diode !ith a band ap o 11 ;KLmol emits liht in !hat reion o the electromanetic radiation spectrum? A) inrared B) ultra:iolet C) :isible 5 blue D) :isible 5 red Ans!er" D Di" 1 #opic" #opic" $ection 21.+ $emiconductor Applications +>) Which one o the ollo!in is a metallic conductor at room temperature but a superconductor at 1 =? A) diamond B) raphite C) ullerene D) potassium ulleride Ans!er" D Di" 1 #opic" #opic" $ection 21.- $uperconductors +1) A particular superconductor has eiht copper atoms on corners and eiht copper atoms on edes o its unit cell. o! man copper atoms are attributed attributed to a sinle unit cell o this superconductor? A) 1 B) & C) * D) 1+ Ans!er" B Di" 1 #opic" #opic" $ection 21.- $uperconductors +2) What is the a:erae oxidation state o Cu in Ca2Ba2Cu&05x i  is in the 2 oxidation state? A) 1 B) 2 C) 52 5 2xL& D) 2  2xL& Ans!er" C Di" ( #opic" #opic" $ection 21.- $uperconductors


+&) What is the a:erae oxidation number o Cu in the 1525& superconductor JBa2Cu&0- i J is in the & oxidation state? A) 2 B) 2.&& C) & D) &.&& Ans!er" B Di" & #opic" #opic" $ection 21.- $uperconductors +() Who disco:ered the phenomenon o superconducti:it in 1311? A) K. 4. Bednor, B) 7. B. uller C) =. A. M ller ller D) . =. 0nnes Ans!er" D Di" 1 #opic" #opic" $ection 21.- $uperconductors +*) What element !as ound to be the irst superconductor o electricit at (.2 = in 1311? A) copper B) iron C) allium D) mercur Ans!er" D Di" 1 #opic" #opic" $ection 21.- $uperconductors ++) Belo! the superconductin transition temperature #c/ superconductors A) become perect conductors. B) become perect manets. C) become perect resistors. D) ail to !or;. Ans!er" A Di" 1 #opic" #opic" $ection 21.- $uperconductors +-) What is the Meissner eect associated !ith superconductors? A) !hen the temperature abo:e !hich the superconductor ails to !or; B) !hen the temperature at !hich the superconductors become perect insulators C) !hen the net manetic ield !ithin the bul; o the superconductor is ,ero D) !hen the net manetic ield !ithin the bul; o the superconductor becomes nearl ininite Ans!er" C Di" 1 #opic" #opic" $ection 21.- $uperconductors +) What structural eatures appear necessar or superconducti:it in the 1525& JBa2Cu&015 Copyright © 2014 Pearson Education, Inc.

superconductor? A) hih metallic character. B) ininite extended laers o Cu and 0 atoms and a ractional oxidation state or Cu C) presence o an inner transition element D) all o the abo:e statements Ans!er" B Di" 2 #opic" #opic" $ection 21.- $uperconductors +3) Which has been ound to be a three dimensional superconductor that cond ucts eEuall in all directions? A) C 6diamond) B) C 6raphite) C) = &C+> D) JBa2Cu&0Ans!er" C Di" 2 #opic" #opic" $ection 21.- $uperconductors ->) Wh are ceramics superior supe rior to metals as structural materials? A) Ceramics are easier to abricate into shapes than metals. B) Ceramics are more malleable than metals. C) Ceramics are more resistant to !ear and corrosion than metals. D) Ceramics ha:e reater impact resistance than metals. Ans!er" C Di" 1 #opic" #opic" $ection 21. Ceramics -1) Which process is used in the abrication o ceramics? A) electrolsis B) reduction C) roastin D) sinterin Ans!er" D Di" 1 #opic" #opic" $ection 21. Ceramics -2) $interin is A) a iltration process throuh a molecular sie:e. B) the process o heatin particles o a po!der belo! the meltin point so that the use toether. C) the process o rapid coolin o a material to ield a superconductin mixture. D) the process o remo:in metals rom ore b passin material throuh a manetic ield. Ans!er" B Di" 1 #opic" #opic" $ection 21. Ceramics -&) Wh are ceramics so much more brittle than metals? 16 Copyright © 2014 Pearson Education, Inc.

A) #he bondin in ceramics has a :er : er hih deree o ionic bondin character. B) #he bondin in ceramics has a :er hih deree o pi bondin character. C) #he bondin in ceramics is hihl nondirectional. D) #he locali,ed bondin in ceramics is hihl d irectional. Ans!er" D Di" 2 #opic" #opic" $ection 21. Ceramics -() What substance has a ratin o 1> on the Mohs hardness scale? A) alumina B) aluminum C) diamond D) talc Ans!er" C Di" 1 #opic" #opic" $ection 21. Ceramics -*) What is the name o the oxide ceramic Be0? A) berllia B) berllic C) berllium ceramic D) berllium oxide Ans!er" A Di" 1 #opic" #opic" $ection 21. Ceramics -+) What is not enerall considered to be a ceramic? A) indium/ 8n B) silica/ $i0 2 C) silicon nitride/ $i& <( D) ,irconia/ i02 Ans!er" A Di" 1 #opic" #opic" $ection 21. Ceramics --) What is the coordination number o $i in $iC that has a diamond5li;e structure? A) 1 B) 2 C) ( D) + Ans!er" C Di" 2 #opic" #opic" $ection 21. Ceramics


-) What is the sol5el process? A) a series o chemical steps that in:ol:es the isolation o Cu$ and then roastin !ith oxen B) a series o chemical steps that in:ol:es the isolation o $0& and then treatment !ith 2$0( C) a series o chemical steps that in:ol:es the snthesis o a metal oxide po!der rom a metal al;oxide D) a series o chemical steps that in:ol:es the thermal d ecomposition o ibers o polacrlonitrile Ans!er" C Di" 1 #opic" #opic" $ection 21. Ceramics -3) What is not part o the sol5el process or the production o titania? A) #iCl(  ( 0C2C&  ( <&  #i60C2C&)(  ( <(Cl 6in ben,ene) B) #i60C2C&)(  ( 20  #i60)(  ( 0C2C& C) 60)&5#i50  05#i560)&  60)&5#i505#i60) &  20 D) ( #i60)(  heat  2 #i20&   20  02 Ans!er" D Di" 2 #opic" #opic" $ection 21. Ceramics >) $ilica 6$i02) can be prepared rom silicon ethoxide b the sol5el process. Write a balanced eEuation or the hdrolsis o silicon ethoxide. A) $iCl(  ( 0C2C&  ( <&  $i60C2C&)(  ( <(Cl 6in ben,ene) B) $i60C2C&)(  ( 20  $i60)(  ( 0C2C& C) $i60C2C&)(  ( 0C&  $i60C&)(  ( 0C2C& D) $i60C&)(  ( 20  $i60)(  ( 0C& Ans!er" B Di" 2 #opic" #opic" $ection 21. Ceramics 1) What is a cermet? A) boron nitrideLepox B) ceramic5metal composite C) ceramic5polmer composite D) silicon carbideLraphite Ans!er" B Di" 1 #opic" #opic" $ection 21.3 Composites

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2) $ilicon nitrideL,irconia is a example o a A) ceramic5ceramic composite. B) ceramic5metal composite. C) ceramic5polmer composite. D) superconductor. Ans!er" A Di" 2 #opic" #opic" $ection 21.3 Composites &) 7elati:e to a bul; sample o old/ nanoparticles o old ha:e A) reater reacti:it and hiher meltin point. B) reater reacti:it and lo!er meltin point. C) lo!er reacti:it and hiher meltin point. D) lo!er reacti:it and lo!er meltin point. Ans!er" B Di" 1 #opic" #opic" J8 Will Will the
() Which o these elements is li;el to be ound in nature as a carbonate? A) element A B) element B C) element C D) element D Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems *) Which o these elements is li;el to be ound in nature as a ree metal? A) element A B) element B C) element C D) element D Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems

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+) Which o these elements is li;el to be ound in nature as a sulide? A) element A B) element B C) element C D) element D Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems -) Which o these elements is li;el to be ound in nature as an oxide? A) element A B) element B C) element C D) element D Ans!er" B Di" 1 #opic" #opic" Conceptual 9roblems ) Which o these elements is li;el to be extracted rom its ore b roastin o a metal sulide? A) element A B) element B C) element C D) element D Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems 3) Which o these elements is li;el to be extracted rom its ore b chemical reduction o a metal oxide? A) element A B) element B C) element C D) element D Ans!er" B Di" 1 #opic" #opic" Conceptual 9roblems 3>) Which o these elements is li;el to be extracted rom its ore b electrolsis? A) element A B) element B C) element C D) element D Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems


se the picture belo! to ans!er the ollo!in Euestions.

31) What diaram !ould describe the molecular orbital picture or the species

#he ollo!in pictures sho! the electron population o  the bands o M0 ener le:els or our dierent materials.

3&) Which o these materials is an insulator? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems 3() Which o these materials is a metal? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 3*) Which o these materials is a semiconductor? A) materials 61) and 62) B) materials 61) and 6() C) materials 62) and 6&) D) materials 6&) and 6() Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems


3+) Which o these materials has the hihest electrical conducti:it? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 3-) Which o these materials has the lo!est electrical conducti:it? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems 3) Which o these materials has an electrical conducti:it that increases !ith an increase in temperature? A) materials 61) and 62) B) materials 61) and 6() C) materials 62) and 6&) D) materials 6&) and 6() Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems 33) Which o these materials has an electrical conducti:it that decreases !ith an increase in temperature? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 1>>) Which o these materials has an electrical conducti:it that remains constant !ith an increase in temperature? A) material 61) B) material 62) C) material 6&) D) material 6() Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems 23 Copyright © 2014 Pearson Education, Inc.

#he ollo!in pictures sho! the electron populations o the composite s-d composite s-d bands bands or our dierent transition metals.

1>1) Which metal has the hihest meltin point? A) metal 61) B) metal 62) C) metal 6&) D) metal 6() Ans!er" C Di" & #opic" #opic" Conceptual 9roblems 1>2) Which metal has the lo!est meltin point? A) metal 61) B) metal 62) C) metal 6&) D) metal 6() Ans!er" D Di" & #opic" #opic" Conceptual 9roblems 1>&) Which is the hardest metal? A) metal 61) B) metal 62) C) metal 6&) D) metal 6() Ans!er" C Di" & #opic" #opic" Conceptual 9roblems


#he ollo!in pictures sho! the electron populations o the composite s-d composite s-d bands bands or $c/ #i/ @/ and n.

1>() Which picture corresponds to $c? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 1>*) Which picture corresponds to #i? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" B Di" 1 #opic" #opic" Conceptual 9roblems 1>+) Which picture corresponds to @? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems


1>-) Which picture corresponds to n? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems #he ollo!in pictures sho! the electron populations o the composite s composite s - d bands bands or J/ Mo/ A/ and Cd.

1>) Which picture corresponds to J? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 1>3) Which picture corresponds to Mo? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" B Di" 1 #opic" #opic" Conceptual 9roblems


11>) Which picture corresponds to A? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems 111) 111) Which picture corresponds to Cd? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" D Di" 1 #opic" #opic" Conceptual 9roblems #he ollo!in picture sho!s the electron populations o the bands o M0 ener le:els or elementar silicon.

112) 8n this picture the band ap is i:en b  letter6s) A) a. B) b. C) c. D) a and b. Ans!er" B Di" 1 #opic" #opic" Conceptual 9roblems 11&) 8n this picture the conduction band is i:en b letter6s) A) a. B) b. C) c. D) a and b. Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 27 Copyright © 2014 Pearson Education, Inc.

11() 8n this picture the :alence band is i:en b letter6s) A) a. B) b. C) c. D) a and b. Ans!er" C Di" 1 #opic" #opic" Conceptual 9roblems

11*) Which picture represents a p5tpe $i semiconductor? A) picture 6A) B) picture 6B) C) both picture 6A) and picture 6B) D) neither picture 6A) nor picture 6B) Ans!er" A Di" 2 #opic" #opic" Conceptual 9roblems 11+) Which picture represents an n5tpe $i $ i semiconductor? A) picture 6A) B) picture 6B) C) both picture 6A) and picture 6B) D) neither picture 6A) nor picture 6B) Ans!er" B Di" 2 #opic" #opic" Conceptual 9roblems

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9icture 61) sho!s the electron populations o the b ands o M0 ener le:els or elementar silicon.

11-) Which picture 61)56() sho!s the electron populations !hen the silicon is doped !ith allium? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" C Di" 2 #opic" #opic" Conceptual 9roblems 11) Which picture 61)56() sho!s the electron populations !hen the silicon is doped !ith arsenic? A) picture 61) B) picture 62) C) picture 6&) D) picture 6() Ans!er" B Di" 2 #opic" #opic" Conceptual 9roblems

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113) Which schematic best represents the electrical resistance :ersus temperature cur:e or a superconductor?

A) A B) B C) C D) none o these Ans!er" A Di" 1 #opic" #opic" Conceptual 9roblems 21.2 Alorithmic Alorithmic Questions 1) Which substance is the best conductor o electricit? A) arsenic B) boron C) sil:er D) tellurium Ans!er" C Di" 1 #opic" #opic" $ection 21.( Bondin in Metals Alo. 0ption" alorithmic 2) Which one o the ollo!in metals is expected to ha:e the hihest meltin point? A) a B)

&) Which element has the smallest ener band ap? A) B B) 8 C) = D) $ Ans!er" C Di" 2 #opic" #opic" $ection 21.* $emiconductors Alo. 0ption" alorithmic () Which one o the ollo!in is an electrical insulator? A) phosphorus B) platinum C) potassium D) ruthenium Ans!er" A Di" 2 #opic" #opic" $ection 21.* $emiconductors Alo. 0ption" alorithmic 21.& $hort Ans!er Questions 1) #he principal source source o chromium is is chromite/ eCr 20( in !hich chromium has an oxidation state o IIIIIIII and iron has an oxidation state o IIIIIIII. Ans!er"  &/  2 Di" 2 #opic" #opic" $ection 21.1 $ources o the Metallic Metallic %lements 2) #he balanced chemical eEuation or the production o sil:er b roastin o its sulide is IIIIIIII. Ans!er" A2$6 s) s)  026 g g )  2 A6 s) s)  $026 g g ) Di" & #opic" #opic" $ection 21.2 Metallur &) Durin the production o iron/ the the ormation o Ca$i0& 6sla) rom the reaction o Ca0 6lime) and $i02 6sand)/ sho!n belo!/ acilitates the separation o the iron rom the anue. Ca06 s) s)  $i026 s) s)  Ca$i0&6l ) 8n this reaction the acidic oxide is IIIIIIII and the basic oxide is IIIIIIII. Ans!er" $i02/ Ca0 Di" 2 #opic" #opic" $ection 21.& 8ron 8ron and $teel $teel


() Accordin to band theor/ the the element ha:in all o its bondin molecular orbitals illed and all o its antibondin orbitals empt in the ( s5& s5&d d composite composite band is IIIIIIII. Ans!er" Cr Di" & #opic" #opic" $ection 21.( Bondin in Metals *) #in #in exists in t!o orms" ra tin and !hite tin. #he electrical conducti:it o ra tin increases !ith an increase in temperature/ !hereas the electrical conducti:it o !hite tin decreases !ith an increase in in temperature. #he orm o tin tin that is a semiconductor semiconductor is IIIIIIII tin. Ans!er" ra Di" 1 #opic" #opic" $ection 21.* $emiconductors +) iht emittin diodes 6%Ds) used in automobile bra;e lihts illuminate 2>> milliseconds aster than con:entional incandescent bra;e lihts. lihts. #he aster illumination illumination i:es the dri:er o a trailin car an additional stoppin distance o IIII IIII eet at ** mph. Ans!er" 1+ Di" 2 #opic" #opic" $ection 21.+ $emiconductor Applications -) #he !a:elenth o liht emitted b the 4a9>.(>As>.+> %D/ !hich has a band ap o 11 ;KLmol/ is IIIIIIII nm. Ans!er" ++1 Di" ( #opic" #opic" $ection 21.+ $emiconductor Applications ) ) Because nanoparticles ha:e a larer percentae o atoms on the surace o the nanoparticle than on the surace o bul; material/ nanoparticles ha:e IIIIIIII meltin points and IIIIIIII chemical reacti:it than the bul; material. Ans!er" lo!er/ reater Di" 2 #opic" #opic" J8 Will Will the

Chapter 21 Review Questions

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