STRUCTURE OF ATOM -2 (Test)

Transcription

1 STRUTURE OF TOM - (Test) o s Model, Hydoge Spectum, Potoelectic effect RE THE INSTRUTIONS REFULLY. Te test is of ous duatio.. Te maximum maks ae Tis test cosists of 55 questios. 4. Fo eac questio i Sectio,, & you will be awaded 3 maks if you ave dakeed oly te bubble coespodig to te coect aswe ad zeo mak if o bubbles ae dakeed. Mius oe (-) mak will be awaded fo wog aswe. 5. Fo eac questio i Sectio E (Matix Matc), you will be awaded maks fo eac ow i wic you ave dakeed te bubble(s) coespodig to te coect aswe. Tus, eac questio i tis sectio caies a maximum of 8 maks. Tee is o egative maks awaded fo icoect aswe(s) i tis Sectio. 6. Fo eac questio i Sectio F (Itege Type), you will be awaded 3 maks if you dake te bubble coespodig to te coect aswe ad zeo mak if o bubble is dakeed. No egative maks will be awaded fo i tis Sectio. 7. Keep You mobiles switced off duig Test i te Halls. SETION (Sigle oect oice Type) Tis Sectio cotais 9 multiple coice questios. Eac questio as fou coices ), ), ) ad ) out of wic ONLY ONE is coect. (Mak oly Oe coice) 9 3 = 87 Maks. Wavelegt of ig eegy tasitio of H atoms is 9. m. alculate te coespodig wavelegt of He +. a..8 m b m c..4 m d m Sol. Fo H atom H R H () Fo He + io R. () He H Fom eqs. () ad () we ave He () 4 (Fo He +, = ) O H 4 H =.8 m.. Te tesold fequecy of a cetai metal is Hz. If ligt of fequecy Hz is icidet o te metal, fid te cut off voltage fo poto electic emissio. Give = Js. Sageeta Kaa P. HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc He O He 4 a V b..0 V c. 0. V d. 0.0 V H 9. 4

2 . Sageeta Kaa P. Sol. Hee, 0 = Hz = Hz = Js. Usig ev 0 = ( 0 ), we get = V 0 = e ( 0 ) ( ) =.0 V 3. electo i o s H-atom as a eegy of -3.4 ev. Wat is te agula mometum of te electo? a Js b Js c Js d Js Sol. Te eegy of a electo i H-atom i a obit is give as 3.6 E = ev ev = ev = Te agula mometum of a electo i t obit is give as m = Js Te ioisatio eegy of He + is 9.6 x 0-8 J atom -.alcuate ioisatio eegy of Li ++ io. a J atom b J atom c J atom d J atom Sol. Eegy of fist obit of Li + He E = - He (costat) E = - Li (costat) Li E Li = Li E He He 3 = ( J atom - ) = J atom - 5. Potoelectic effect sows: a. Paticle-like beaviou of ligt b. Wave-like beaviou of ligt c. ot wave-like ad paticle-like beaviou of ligt d. Neite wave-like o paticle-like beaviou of ligt Sol. It is a expeimetal evidece fo paticle atue of electo 6. Te adius of H-atom i goud state is 0.53 Å. Radius of fist obit of Li + i Å is: a b. 0.3 c d. 0.5 H 0.53 Sol. Li = = 0.76 Å 3. Sageeta Kaa P. HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

3 . Sageeta Kaa P. 7. Of te followig wic of te statemet(s) egadig o teoy is wog: a. Kietic eegy of a electo is alf of te magitude of its potetial eegy b. Kietic eegy of a electo is egative of total eegy of electo c. Eegy of electo deceases wit icease i te value of te piciple quatum umbe d. Te ioizatio eegy of H-atom i te fist excited state is egative of oe fout of te eegy of a electo i te goud state Sol. Eegy of electo iceases wit icease i E 8. Te atio of te diffeece i eegy of electo betwee te fist ad secod o s obits to tat betwee secod ad tid o s obits is: a. /3 b. 7/5 c. 9/4 d. 4/9 E Sol. E = (E, Fid E) 3 / 4 = (E3 E ) 5 / Te electoic velocity i te fout o s obit of ydoge is u. Te velocity of te electo i te fist obit would be: a. 4u b. 6u c. u/4 d. u/6 Sol. u = u 0. How muc eegy sould be absobed by a ydoge atom i goud state to eac fist excited state? a. +.5 ev b. 3.4 ev c. 3.4 ev d. 0. ev Sol. Fo te electo to go to secod obit, E = E E = -3.4 ( -3.6) = = 0. ev. Te distace betwee 3d ad d obits i te ydoge atom is Sol. a cm b cm c cm d cm 3 = 0.59 Å 3 = 4.76 Å = 0.59 Å =.6 Å 0.59Å. 3 = Å =.645 Å. Velocity of electo i te secod obit of H-atom as compaed to tat of ligt is ealy a. 0 b. 00 c. 74 d. 548 V Sol. V ligt electo V V e o V V e 74. Sageeta Kaa P. 3 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

4 . Sageeta Kaa P. 3. Te adius of wic of te followig obits is same as tat of te fist o s obit of ydoge atom? a. He + ( = ) b. Li + ( = ) c. Li + ( = 3) d. e 3+ ( = ) Sol. R H = 0.59 Å 3 H e 0.59 Å = = 0.59 Å 4 4. If te eegy diffeece betwee te goud state of a atom ad its excited state is J, te wavelegt of poto equied to poduce te tasitio: Sol. a m b m c m d m c E = = 34 o = 6.60 Js 3 0 ms = J = m 5. Te splittig of spectal lies ude te ifluece of a electic field is called: 8 c E a. Rama effect b. eema effect c. ompto effect d. Stak effect 6. Wic expeimetal obsevatio coectly accout fo te peomeo? Expeimetal obsevatio Peomeo a. X-ays specta atomic mass b. -paticle scatteig Quatized electo obit c. Potoelectic effect wave atue d. Emissio specta Quatizatio of eegy Sol. Emissio spectum is key ote of quatizatio of eegy 7. ccodig to o s teoy te agula mometum of a electo i te fout obit is a. b. Sol. gula mometum of a electo is give as m = 8. Wic of te followig coceig o s model is false? c. 3 3 d. a. Pedicts tat pobability of electo ea ucleus is moe b. gula mometum of electo i H atom = c. Itoduces te idea of statioay states d. Explais lie spectum of ydoge. Sol. o s model does ot talk about pobability of electos.. Sageeta Kaa P. 4 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

5 . Sageeta Kaa P. 9. Te eegy equied to emove a electo fom metal X is J. Te maximum wavelegt of ligt tat ca potoeject a electo fom metal X is a m b. 60 m c. 600 m d m c Sol. E = c Js 3 08 m s- = m = 600 mm E J 0. Te eegy of fist sell i ydoge is -3.6 ev. Te eegy of secod sell will be: a ev b. -0. ev c. - ev d. 3.0 ev. Te umbe of potos of ligt avig wave umbe x i J of eegy souce is a. cx c b. x Sol. c E = = c as E = J = c o = c c. cx cx x d. c. If i o s model, fo uielectoic atom, time peiod of evolutio is epeseted as T, wee epesets sell o. ad epesets atomic umbe te te value of T, : T, will be: a. 8 : b. : 8 c. : d. : 3 3 T, Sol. T ; T 4 8 3, 3. Wic of te followig statemet is ot coect about potoelectic effect? a. It establised te existece of potos b. Te eegy of te ejected electo is popotioal to te fequecy of te adiatio c. Icease i itesity of poto ligt iceases poto cuet d. Te potoelectic effect explai te wave atue of ligt 4. Te atio of agula mometum of electo i two successive obit is a (a > ) ad tei diffeece is b. Te a/b is equal to : a. b. Sol. gula mometum i two successive obitals ae a ad a. b b c.. ad d... Sageeta Kaa P. 5 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

6 K.E. K.E.. Sageeta Kaa P. 5. electo is movig oud te ucleus of a ydoge atom i a cicula obit of adius. Te coulombic foce F betwee te two is : K 40 a. Sol. F = K Ke Q Q b. e K K c. 6. I wic of te followig systems will te adius of te fist obit is miimum : e K d. Ke a. oubly ioized litium b. Sigly ioized elium c. euteum atom d. Hydoge atom Sol. H Te wok fuctio fo metals, ad espectively ad.9 ev,.00 ev ad 5.0 ev. Wic of tem will emit poto electos if exposed to adiatios of wavelegt 400 Å. a. oly b. ad oly c. ll of tese d. Noe of tese 34 8 c 6, Sol. E = v = ev = 3 ev Wok fuctio sould be lowe ta 3eV to eject electo 8. Te agula mometum of electo i ydoge atom is popotioal to: a. b. Sol. gula mometum = = 0.59Å c. d. gula mometum 9. Potoelecto emissio is obseved fo tee diffeet metals, ad. Te kietic eegy of te fastest potoelectos vesus fequecy is plotted fo eac metal. Wic of te followig gap sows te peomeo coectly? [If,, ae Na, K, s] a. b. Fequecy () Fequecy (). Sageeta Kaa P. 6 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

7 K.E. K.E.. Sageeta Kaa P. c. d. Fequecy () Fequecy () So. Kietic eegy of potoelectos iceases wit icease i fequecy of icidet adiatio. Te gaps fo tee metals,, will be paallel to eac ote & tesold fequecy will be lowest fo. SETION (ssetio ad Reaso) Negative Makig Tis Sectio cotais 6 multiple coice questios. Eac questio as fou coices ), ), ) ad ) out of wic ONLY ONE is coect. 6 3 = 8 Maks () Statemet & Statemet - ae tue; Statemet is te coect explaatio of Statemet -. () Statemet & Statemet - ae tue but Statemet is ot a coect explaatio fo Statemet-. () Statemet is tue ad Statemet - is false. () Statemet is false ad Statemet - is tue. age. Statemet : atio of aode ays is foud diffeet fo diffeet gases. Mass Statemet -: olo i discage tube deped o atue of gas. a. (a) b. (b) c. (c) d. (d) Sol. e/m atio of aode ays vaies wit te gas filled i te discage tube.. Statemet-: Kietic eegy of potoelectos is liealy popotioal to te fequecy of te icidet adiatio. Statemet-: Eac poto of ligt causes te emissio of oly oe potoelecto. a. (a) b. (b) c. (c) d. (d) Sol. Kietic eegy of potoelecto deped o te of icidet adiatio. ccodig to te Eistei s teoy of potoelectic effect, oe poto ca eject oly oe potoelecto fom te metal suface. 3. Statemet-: Te sotest wavelegt of tasitio of Lyma seies is obseved we electo jumps fom obit umbe, = to =. c Statemet-: Sice te wavelegt of tasitio is give by E, maximum eegy tasitio will ave lowest. a. (a) b. (b) c. (c) d. (d) 4. Statemet-: Limitig lie i te alme seies of H spectum as a wavelegt of Statemet-: Limitig lie is obtaied fo a jump of electo fom = 3 to =. 4 R H a. (a) b. (b) c. (c) d. (d). Sageeta Kaa P. 7 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

8 . Sageeta Kaa P. 5. Statemet-: Potoelectic effect pove wave atue of Radiatio Statemet-: Potocuet deped o itesity of icidet Radiatio a. (a) b. (b) c. (c) d. (d) 6. Statemet-: o s teoy is based o Plak s quatum Mecaics Statemet-: ocept of statioay state fo electo was give by o. a. (a) b. (b) c. (c) d. (d) SETION (Paagap Type) Tis Sectio cotais 3 paagaps. Eac of tese questios as fou coices ), ), ) ad ) out of wic ONLY ONE is coect. (Mak oly oe) 9 3 = 7 Maks Passage ccodig to Plack s quatum teoy of adiatio, te adiat eegy is emitted o absobed discotiuously i te fom of quata. Te eegy of a quatum is give by E =, wee is te fequecy of adiatio. Moeove, a body ca emit o absob eegy oly i a itegal multiple of quatum.. Plack s quatum teoy of adiatio favous te followig atue of electomagetic adiatio: a. Paticle atue b. Wave atue c. ual atue d. oe of tese. Te eegy associated wit oe poto of wavelegt 3000 Å is: a. 5.4 x 0 9 J b x 0-9 J c x 0 6 J d x 0 9 J 3. Wic of te followig is ot te coect epesetatio of Eistei s potoelectic equatio? a. m ( 0 ) b. 0 m c. W m (W = Wok Fuctio) d. m ( 0 ) Passage ccodig to o s teoy, te eegy eleased duig te de excitatio of electo i a atom is quatized ad is equal to te diffeece of te eegies of te two levels. We a electo jumps fom eegy level to level, te eegy eleased coespods to te wave umbe give by te followig equatio R Wee R is costat called Rydbeg costat. Its value is foud to e equal to cm. Eac tasitio of electo fom a ige eegy level to a lowe eegy level gives ise to a discete spectal lie i te emissio spectum of te atom ude cosideatio.. Sageeta Kaa P. 8 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

9 . Sageeta Kaa P. 4. Te ame ad te egio of te seies of spectal lies i ydoge spectum obtaied by te tasitio of a electo fom = 4, 5, 6, 7,.. to = 3 ae: a. Pasce seies, U.V. b. alme seies, visible c. Pasce seies, I.R. d. alme seies, U.V. 5. spectal lie i te alme seies of ydoge spectum coespods to 656Å. Te tasitio ivolved is: a. b. 3 c. 4 3 d To wic of te followig is o s teoy applicable? a. +4 b. Li + c. e + d. O Paagap-3 Elemets ae composed of tiy paticles kow as atoms. toms ae made of fudametal paticles (e,p,). ccodig to Rutefod s tomic Model p, ae located i Nucleus. o s model explaied te existece of cicula obits (eegy levels) aoud te ucleus. o s model ca explai te spectum of ydogeic species ad elps i fid e,v, (eegy, velocity ad adius) i t obit. 7. Te atio of 4 ad 3 fo ydoge atom ad tat of Li + io: a. : 3 b. 3 : c. : 9 d. 6 : 3 4 H H Li 3 Sol. 3 Li Li H 8. Te value of electo static potetial eegy betwee two caged paticle a. mv e qq e b. c. d I a obit te velocity of a electo i excited state of H-atom is cm/s. Wat is te cicumfeece i tis obit. a Å b. 3.3 Å c Å d Å z Sol. V = = icumfeece = = 0.59 Å 7 = 3.3 Å. Sageeta Kaa P. 9 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

10 . Sageeta Kaa P. SETION (Moe ta Oe swe Type) Negative Makig Tis Sectio cotais 3 multiple coice questios. Eac questio as fou coices ), ), ) ad ) out of wic ONE OR MORE may be coect. 3 3 = 9 Maks. I a electo tasitio of ydoge atom, obit agula mometum of a electo may cage by: a. b., Sol. age i agula mometum = ( ). 3 Possible values will be,,,.. ad is ot possible 4 = 3 = = 3 Fo above tasitios, ad 3 i ydoge like atoms, select te coect elatio(s). a. 3 = + b. 3 = c. d. 4 c. 3 = + d. 3 =, Sol. E 3 = E + E 3 = + 3 = + c c c ; ; 3 = Let, V ad E ae te adius of te obit, speed of te electo ad te total eegy of te electo espectively. Wic of te followig quatities ae popotioal to te No. of sell? a. E b. v c. E v, Sol. v cm/ sec (b) v = cm V E = J (c) E Tese elatios sow tat v ad E v will be popotioal to te picipal quatum umbe. d. E. Sageeta Kaa P. 0 HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

11 . Sageeta Kaa P. SETION E (Matix Type) Tis Sectio cotais questios. Eac questio as fou coices (,, ad ) give i olum I ad five statemets (p, q,, ad s) i olum II. 8 = 6 Maks. Matc te olum-i wit olum-ii. olum I olum II () Kietic eegy (p) Potetial eegy () Potetial eegy + Kietic eegy (q) - / () Potetial eegy () - Total eegy () Kietic eegy (s) 0 Total eegy Sol. q; s; p,. Matc olum I wit olum II olum I olum II () Radius of o obit (P) Iceases o iceasig sell umbe () Kietic eegy of a electo i o obit (Q) Popotioal to () Speed of a electo i o obit (R) Popotioal to 3 () Time peiod of a electo i oe complete evolutio i a o obit (S) Iceases o iceasig atomic umbe Sol. () P,Q; () S; () S; () P,R 0.59 () P, Q 9 () K.E..7 0 S () V S 3 () P, R SETION F (Itege Type) No Negative Makig Tis Sectio cotais 6 questios. Te aswe to eac questio is a Sigle igit Itege agig fom 0 to 0. Te coect digit below te questio umbe i te ORS is to be bubbled. 6 3 = 8. electo i te goud state of H atom absobs eegy equal to 0. ev. Fid te excited state to wic te electo will be pomoted. Sol. Eegy of electo i goud state = -3.6 ev Eegy supplied = 0. ev T.E. = -3.4 E = ev ev = -3.4 ev. Sageeta Kaa P. HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc

12 . Sageeta Kaa P. 3.6 ev = -3.4 ev = ; = 4 ; =. Ioisatio potetial of ydoge atom is 3.6 ev. If goud state of H-atom is excited by moocomatic adiatios of. ev, te umbe of spectal lies emitted by H-atom o deexcitatio will be: Sol. E 3.6 lso E = E E 0. = = 3 Tus, deexcitatio will lead spectal lies = = (3 ) = 3 3. Te speed of electo i te fist obit of ydoge atom is 0 6 ms. Te speed of te electo i te same obit of He + atom is x 0 6 ms -, x is Sol. ( ) = () H = 0 6 He = ms = 4 4. Te amout of eegy equied to emove te electo fom a Li + io i its goud state is ow may times geate ta te amout of eegy equied to emove te electo fom a H-atom i its goud state: Sol. E Li EH E Li 3 EH = 9 5. Wat would be te maximum umbe of emissio lies fo atomic ydoge tat you would expect to see wit te aked eye if te oly electoic eegy levels ivolved ae tose as sow i te Figue? = 7 = 6 = 5 = 4 = 3 = = Sol. 5 [7 ; 6 ; 5 ; 4 ; 3 ] 6. Te speed of a electo i a obit of ydoge atom is m/sec. Total umbe of waves fomed by te electo i oe complete evolutio i tis obit. Sol. 5 ccodig to o s teoy, V m / sec Fo Hydoge atom, = = (5) V ccodig to de oglie, total umbe of waves made by a electo i oe complete evolutio Sell umbe = (5). Sageeta Kaa P. HEMISTRY OHING IRLE G:\Obj-tomic Stuctue-.doc