28 64 Ni is - g/mole Se (D)

Transcription

1 EXERCISE-0 CHECK YOUR GRASP SELECT THE CORRECT ALTERNATIVE (ONLY ONE CORRECT ANSWER). Te element aving no neutron in te nucleus of its atom is - (A) ydrogen (B) nitrogen (C) elium (D) boron. Te particles present in te nucleus of an atom are - (A) te proton and te electron (C) te proton and te neutron (B) te electron and te neutron (D) none of tese 3. Te fraction of volume occupied by te nucleus wit respect to te total volume of an atom is - (A) 0 5 (B) 0 5 (C) 0 30 (D) Wic of te following is iso-electronic wit neon - (A) O (B) F + (C) Mg (D) Na 5. Te approximate size of te nucleus of 8 64 Ni is - (A) 3 fm (B) 4 fm (C) 5 fm (D) fm 6. Wic is true about an electron - (A) rest mass of electron is (B) mass of electron increases wit te increase in velocity (C) molar mass of electron is (D) e/m of electron is coulomb/g 7. An isotone of 76 3Ge is - (A) 77 3 Ge (B) g g/mole As (C) Se (D) Se 8. Wen alpa particles are sent troug a tin metal foil, most of tem go straigt troug te foil because - (A) alpa particles are muc eavier tan electrons (B) alpa particles are positively carged (C) most part of te atom is empty space (D) alpa particles move wit ig speed 9. Many elements ave nonintegral atomic masses because - (A) tey ave isotopes (B) teir isotopes ave non-integral masses (C) teir isotopes ave different masses (D) te constituents, neutrons, protons and electrons combine to give fractional masses 0. Te MRI (magnetic resonance imaging) body scanners used in ospitals operate wit 400 MHz radio frequency energy. Te wavelengt corresponding to tis radio frequency is - (A) 0.75 m (B) 0.75 cm (C).5 m (D) cm. Poton of wic ligt as maximum energy - (A) Red (B) Blue (C) Violet (D) Green. Te value of Planck's constant is Js. Te velocity of ligt is m/sec. Wic value is closest to te wavelengt in nanometer of a quantum of ligt wit frequency of sec - (A) (B) 4 0 (C) (D) Bor's teory is not applicable to - (A) He (B) Li + (C) He + (D) te H-atom

2 4. Wat is likely to be principal quantum number for a circular orbit of diameter 0 nm of te ydrogen atom if we assume Bor orbit be te same as tat represented by te principal quantum number? (A) 0 (B) 4 (C) (D) 6 5. Wic is te correct relationsip - (A) E of H = / E of He + = /3 E 3 of Li + = /4 E 4 of Be 3+ (B) E (H) = E (He + ) = E 3 (Li + ) = E 4 (Be 3+ ) (C) E (H) = E (He + ) = 3E 3 (Li + ) = 4E 4 (Be 3+ ) (D) No relation 6. If te value of E = 78.4 kcal/mole, te order of te orbit in ydrogen atom is - (A) 4 (B) 3 (C) (D) 7. If velocity of an electron in st orbit of H atom is V, wat will be te velocity of 3 rd orbit of Li + - (A) V (B) V/3 (C) 3 V (D) 9 V 8. In a certain electronic transition in te ydrogen atoms from an initial state () to a final state (), te difference in te orbit radius (r r ) is 4 times te first Bor radius. Identify te transition - (A) 5 (B) 5 (C) 8 3 (D) Matc te following - (a) Energy of ground state of He + (i) 6.04 ev (b) Potential energy of I orbit of H-atom (ii) 7. ev (c) Kinetic energy of II excited state of He + (iii) J (d) Ionisation potential of He + (iv) 54.4 ev (A) A (i), B (ii), C (iii), D (iv) (C) A (iv), B (ii), C (i), D (iii) (B) A (iv), B (iii), C (ii), D (i) (D) A (ii), B (iii), C (i), D (iv) 0. Te energy of ydrogen atom in its ground state is 3.6 ev. Te energy of te level corresponding to n = 5 - (A) 0.54 ev (B) 5.40 ev (C) 0.85 ev (D).7 ev. Total no. of lines in Lyman series of H spectrum will be - (were n = no. of orbits) (A) n (B) n (C) n (D) n (n + ). Te spectrum of He + is expected to be similar to tat of - (A) Li + (B) He (C) H (D) Na 3. Wat possibly can te ratio be of te de Broglie wavelengts for two electrons aving te same initial energy and accelerated troug 50 volts and 00 volts? (A) 3 : 0 (B) 0 : 3 (C) : (D) : 4. Te uncertainty in te momentum of an electron is kg m s. Te uncertainty of its position will be ( = kg m s ) - (A) m (B) m (C) m (D) m 5. An -particle is accelerated troug a potential difference of V volts from rest. Te de-broglie's wavelengt associated wit it is - (A) 50 A V (B) 0.86 A V 6. Te orbital wit zero angular momentum is - (C) 0.0 A V (A) s (B) p (C) d (D) f (D) A V

3 7. Wic of te following is electronic configuration of Cu + (Z = 9) - (A) [Ar]4s 3d 8 (B) [Ar]4s 3d 0 4p (C) [Ar]4s 3d 0 (D) [Ar] 3d 9 8. Te electronic configuration of te Mn 4+ ion is - (A) 3d 4 4s 0 (B) 3d 4s (C) 3d 4s (D) 3d 3 4s 0 9. Wic of te following ions as te maximum number of unpaired d-electrons - (A) Zn + (B) Fe + (C) Ni 3+ (D) Cu Te total spin resulting from a d 7 configuration is - (A) (B) (C) 5/ (D) 3/ 3. Given K L M N 8 Te number of electrons present in = is - (A) 3 (B) 6 (C) 5 (D) 4 3. Te configuration s s p 5 3s sows te - (A) ground state of te fluorine atom (C) excited state of te neon atom 3 3. Te value and m for te last electron in te Cl ion are - (B) excited state of te fluorine atom (D) excited state of O ion (A) and (B) and + (C) 3 and (D) and 3 4. In wic transition, one quantum of energy is emitted - (A) n = 4 n = (B) n = 3 n = (C) n = 4 n = (D) n = n = 3 5. Coose te correct relation on te basis of Bor's teory - (A) velocity of electron n (C) radius of orbit n Z (B) frequency of revolution (D) force on electron 3 6. Te magnitude of te spin angular momentum of an electron is given by - (A) S = s(s ) (B) S = s (C) S = 3 (D) S = ± 3 7. Te cange in orbital angular momentum corresponding to an electron transition inside a ydrogen atom can be - (A) 4 (B) 3 8. In wic of tese options do bot constituents of te pair ave te same magnetic moment - (A) Zn + and Cu + (B) Co + and Ni + (C) Mn 4+ and Co + (D) Mg + and Sc + (C) Z n 3 4 (D) Z n 3 8 CHECK YOUR GRASP ANSWER KEY EXERCISE - Qu e Ans. A C A A C A,B,C,D B,D A,C A,C A C B A,C B B Qu e Ans. C A A C A B C D C C A D D B D Qu e Ans. A C D A,B,C,D A,B,D A,C B,C A,C

4 EXERCISE 0 BRAIN TEASERS SELECT THE CORRECT ALTERNATIVES (ONE OR MORE THEN ONE CORRECT ANSWERS). Te maximum energy is present in any electron at :- (A) Nucleus (B) Ground state (C) First excited state (D) Infinite distance from te nucleus. Wic electronic level would allow te ydrogen atom to absorb a poton but not to emit a poton :- (A) 3s (B) p (C) s (D) s 3. Te tird line in Balmer series corresponds to an electronic transition between wic Bor's orbits in ydrogen :- (A) 5 3 (B) 5 (C) 4 3 (D) 4 4. Correct set of four quantum numbers for valence electron of rubidium (Z = 37) is :- (A) 5, 0, 0, + (B) 5,, 0, + (C) 5,,, + (D) 6, 0, 0, + 5. Te orbital diagram in wic te Aufbau's principle is violated is :- (A) s p x p y p z (B) s px p y p z (C) s p x p y p z px py pz (D) s 6. Te total number of neutrons in dipositive zinc ions wit mass number 70 is :- (A) 34 (B) 40 (C) 36 (D) Wic of te following sets of quantum numbers represent an impossible arrangement :- n l m m s (A) 3 (B) (C) 3 3 (D) Te explanation for te presence of tree unpaired electrons in te nitrogen atom can be given by :- (A) Pauli's exclusions principle (C) Aufbau's principle (B) Hund's rule (D) Uncertainty principle 9. Te electronic configuration of an element is s s p 6 3s 3p 6 3d 5 4s. Tis represents its :- (A) Excited state (B) Ground state (C) Cationic form (D) None 0. Wic of te following as maximum number of unpaired electron (atomic number of Fe 6) :- (A) Fe (B) Fe (II) (C) Fe (III) (D) Fe (IV). Wic quantum number is not related wit Scrodinger equation :- (A) Principal (B) Azimutal (C) Magnetic (D) Spin. If 0 is te tresold wavelengt for potoelectric emission, wavelengt of ligt falling on te surface of metal, and m mass of electron, ten de Broglie wavelengt of emitted electron is :- (A) ( 0 ) mc( 0 ) (B) ( 0 ) mc 0 ) (C) ( 0 ) mc 0 ) (D) 0 mc

5 3. It is known tat atom contain protons, neutrons and electrons. If te mass of neutron is assumed to alf of its original value were as tat of proton is assumed to be twice of its original value ten te atomic mass of 4 6 C will be :- (A) same (C) 4.8 % more (B) 5 % more (D) 8.5 % less 4. Give te correct order of initials T (true) or F (false) for following statements :- (I) If an ion as electrons in K sell, 8 electrons in L sell and 6 electrons in M sell, ten number of S electrons present in tat element is 6. (II) Te maximum number of electrons in a subsell is given by n (III) If electron as magnetic quantam number, ten it cannot be present in s-orbital. (IV) Only one radial node is present in 3p orbital. (A) TTFF (B) FFTF (C) TFTT (D) FFTF 5. Te sortest wavelengt of He + in Balmer series is x, ten longest wavelengt in te Pascene series of Li + is :- (A) 36x 5 (B) 6x 7 (C) 9x 5 (D) 5x 9 6. An electron in a ydrogen atom in its ground state absorbs energy equal to ionisation energy of Li +. Te wavelengt of te emitted electron is :- (A) m (B).7 Å (C) nm (D) 3.33 pm 7. In compound FeCl te orbital angular momentum of last electron in its cation & magnetic moment (in Bor Magneton) of tis compound are :- (A) ( 6 ), 35 (B) ( 6 ), 4 (C) 0, 35 (D) none of tese 8. An electron, a proton and an alpa particle ave kinetic energy of 6 E, 4E and E respectively. Wat is te qualitative order of teir de Broglie wavelengts :- (A) e > p = (B) p = > e (C) p > e > (D) < e >> p 9. Question : Is te specie paramagnetic? STATE- : Te atomic number of specie is 9. STATE- : Te carge on te specie is +. (A) Statements () alone is sufficient but statement () is not sufficient (B) Statement () alone is sufficient but statement () is not sufficient (C) Bot statement togeter are sufficient but neiter statement alone is sufficient (D) Statement () & () togeter are not sufficient 0. Given H for te process Li (g) Li +3 (g) + 3e is 9800 kj/mole & IE for Li is 50 ten IE & IE of Li + are respectively (approx value) :- (A) 775, 7505 (B) 980, 50 (C) 775, 980 (D) Data insufficient. Te ratio of difference in wavelengts of st and nd lines of Lyman series in H-like atom to difference in wavelengt for nd and 3 rd lines of same series is :- (A).5 : (B) 3.5 : (C) 4.5 : (D) 5.5 :

6 . Wic of te following statement is INCORRECT. (A) (B) e ratio for canal rays is maximum for ydrogen ion. m e ratio for catode rays is independent of te gas taken. m (C) Te nature of canal rays is dependent on te electrode material. e (D) Te m ratio for electron is expressed as E,wen te catode rays go undeflected under te B V influence of electric field (E), magnetic field (B) and V is potential difference applied across electrodes. 3. Te quantum numbers of four electrons (e to e4) are given below :- n m s e / e 4 0 / e 3 3 / e 4 3 / Te correct order of decreasing energy of tese electrons is : (A) e4 > e3 > e > e (C) e3 > e > e4 > e (B) e > e3 > e4 > e (D) none 4. If radius of second stationary orbit (in Bor's atom) is R. Ten radius of tird orbit will be :- (A) R/3 (B) 9R (C) R/9 (D).5 R 5. Te wavelengt associated wit a gold weiging 00 g and moving at a speed of 5 m/ is of te order :- (A) 0 0 m (B) 0 0 m (C) 0 30 m (D) 0 40 m 6. If te nitrogen atom ad electronic configuration s 7, it would ave energy lower tat of normal ground state configuration s s p 3, because te electrons would be closer to te nucleus. Yet s 7 is not observed because it violates :- (A) Heisenberg uncertainty principle (C) Pauli's exclusion principle 7. From te following observations predict te type of orbital : Observation : x y plane acts as nodal plane (B) Hunds rule (D) Bor postulate of stationary orbits Observation : Te angular function of te orbital intersect te tree axis at origin only. Observation 3 : R (r)v/s r curve is obtained for te orbital is R (r) r (A) 5p z (B) 6d xy (C) 6d x y (D) 6 d yz 8. Question : Is te orbital of ydrogen atom 3p x? STATE : Te radial function of te orbital is R(r) = 9 6a STATE : Te orbital as radial node & 0 angular node. 3 / 0 (4 ) e /, = r (A) Statement () alone is sufficient. (B) Statement () alone is sufficient (C) Bot togeter is sufficient (D) Neiter is sufficient

7 9. Consider te following nuclear reactions involving X & Y. X Y + 4 He Y 8 O 8 + H If bot neutrons as well as protons in bot te sides are conserved in nuclear reaction ten identify period number of X & moles of neutrons in 4.6 g of X (A) 3,.4 N A (B) 3,.4 (C), 4.6 (D) 3, 0. N A 3 0. Electromagnetic radiations aving = 30 Å are subjected to a metal seet aving work function =.8 ev. Wat will be te velocity of potoelectrons wit maximum Kinetic Energy... (A) 0, no emission will occur (B) m/s (C) m/s (D) m/s 3. If in Bor's model, for unielectronic atom, time period of revolution is represented as T n,z were n represents sell no. and z represents atomic number ten te value of T, : T, will be :- (A) 8 : (B) : 8 (C) : (D) None of tese 3. Column I & Column II contain data on Scrondinger Wave-Mecanical model, were symbols ave teir usual meanings. Matc te columns :- Column I Column II (Type of orbital) (A) r (p) 4s r (B) r 4r (q) 5p x (C) (, ) = K (independent of ) (r) 3s (D) atleast one angular node is present (s) 6d xy 3 3. Wic orbital is non-directional :- (A) s (B) p (C) d (D) All 3 4. A ydrogen - like atom as ground state binding energy.4 ev. Ten : (A) its atomic number is 3 (B) an electron of 90 ev can excite it to a iger state (C) an 80 ev electron cannot excite it to a iger state (D) an electron of 8. ev and a poton of 9.8 ev are emitted wen a 00 ev electron interacts wit it 3 5. Uncertainty in position is twice te uncertainty in momentum Uncertainty in velocity is :- (A) (B) m (C) m (D) For wic orbital angular probability distribution is maximum at an angle of 45 to te axial direction :- (A) d x y (B) d z (C) d xy (D) P x

8 3 7. Wic orbit would be te first to ave 'g' subsell :- (A) 3 rd (B) 4 t (C) 5 t (D) 6 t 3 8. Te decreasing order of energy of te 3d, 4s, 3p, 3s orbitals is :- (A) 3d > 3s > 4s > 3p (B) 3s > 4s > 3p > 3d (C) 3d > 4s > 3p > 3s (D) 4s > 3d > 3s > 3p 3 9. If n and are respectively te principle and azimutal quantum numbers, ten te expression for calculating te total number of electrons in any orbit is :- (A) n ( ) (B) n ( ) (C) n 0 ( ) 4 0. If wavelengt is equal to te distance travelled by te electron in one second, ten :- (A) p (B) m 4. According to Scrodinger model nature of electron in an atom is as :- (A) Particles only (C) Bot simultaneously 4. Wic describes orbital :- (C) p (B) Wave only (D) (D) n 0 ( ) m (D) Sometimes waves and sometimes particle (A) (B) (C) (D) All 4 3. In order to ave te same wavelengt for te electron (mass m e ) and te neutron (mass m n ) teir velocities sould be in te ratio (electron velocity/neutron velocity) :- (A) m n /m e (B) m n m e (C) m e /m n (D) one 4 4. Te quantum numbers +/ and / for te electron spin represent :- (A) Rotation of te electron in clockwise and anticlockwise direction respectively. (B) Rotation of te electron in anticlockwise and clockwise direction respectively. (C) Magnetic moment of te electron pointing up and down respectively. (D) Two quantum mecanical spin states wic ave no classifical analogue Wic is true about :- (A) represents te probability of finding an electron around te nucleus (B) represent te amplitude of te electron wave (C) Bot A and B (D) None of tese 4 6. Consider an electron in te n t orbit of a ydrogen atom in te Bor model. Te circumference of te orbit can be expressed in terms of te de Broglie wavelengt of te electron as :- (A) (0.59) n (B) n (C) (3.6) (D) n 4 7. A particle X moving wit a certain velocity as a debroglie wave lengt of A. If particle Y as a mass of 5% tat of X and velocity 75% tat of X, debroglies wave lengt of Y will be :- (A) 3 A (B) 5.33 A (C) 6.88 A (D) 48 A 4 8. Wat are te values of te orbital angular momentum of an electron in te orbitals s, 3s, 3d and p :- (A) 0, 0, 6, (B),, 4, (C) 0,, 6, 3 (D) 0, 0, 0, If m = magnetic quantum number and = azimutal quantum number ten :- (A) m = + (B) m = + (C) = m (D) = m +

9 5 0. Te number of unpaired electrons in Mn 4+ (Z = 5) is :- (A) Four (B) Two (C) Five (D) Tree 5. After np orbitals are filled, te next orbital filled will be :- (A) (n + ) s (B) (n + ) p (C) (n + ) d (D) (n + ) s 5. Te value of te magnetic moment of a particular ion is.83 Bor magneton. Te ion is :- (A) Fe + (B) Ni + (C) Mn + (D) Co In Bor's model of te ydrogen atom te ratio between te period of revolution of an electron in te orbit of n = to te period of te revolution of te electron in te orbit n = is :- (A) : (B) : (C) : 4 (D) : Let be te frequency of te series limit of te Lyman series, be te frequency of te first line of te lyman series, and 3 be te frequency of te series limit of te Balmer series :- (A) = 3 (B) = 3 (C) 3 = / ( 3 ) (D) + = Te energies of energy levels A, B and C for a given atom are in te sequence E A < E B < E C. If te radiations of wavelengts, and 3 are emitted due to te atomic transitions C to B, B to A and C to A respectively ten wic of te following relations is correct :- (A) = 0 (B) 3 = + (C) 3 = + (D) 3 = 5 6. Te wavelengts of potons emitted by electron transition between two similar levels in H and He + are and respectively. Ten :- (A) = (B) = (C) = / (D) = / If first ionization potential of an atom is 6 V, ten te first excitation potential will be :- (A) 0. V (B) V (C) 4 V (D) 6 V 5 8. In wic transition minimum energy is emitted :- (A) (B) (C) 3 (D) n (n ) (n 4) 5 9. No. of visible lines wen an electron returns from 5 t orbit to ground state in H spectrum :- (A) 5 (B) 4 (C) 3 (D) 0 BRAIN TEASERS ANSWER KEY EXERCISE - Q u e An s. D D B A B B C B B C D A C C B Q u e An s. B B A C A B C C D C C D B B C Q u e. 3 3 (A) ( B) ( C) ( D ) An s. D p p,q,s p,r q,s A A,C,D C C C C D D B B Q u e An s. A D B D B A C D A B D A D D B Q u e An s. D C

10 EXERCISE 03 MISCELLANEOUS TYPE QUESTIONS TRUE / FALSE. Te electron density in xy plane of 3d orbital is zero.. 3d 6 configuration is more stable tan 3d 5. x y 3. Te potential energy of an electron in an orbit is twice in magnitude as compared to its kinetic energy. 4. Te increasing order for te values of e/m (carge/mass) for electron (e), proton (p), neutron (n) and alpa particle () is n < < p < e. 5. Te orbital 3d xy as no probability of finding electron along x and y-axis. FILL IN THE BLANKS. Nitrogen as an atomic number of 7 and oxygen as an atomic number of 8. Te total number of electrons in te nitrate ion (NO ) is /is te angular momentum of te electron in te... orbit of He An emission spectrum as electromagnetic radiation of definite Te maximum number of electrons tat can be accommodated in all te orbitals for wic = 3 is Te values of n and n in te Pascen spectral series of ydrogen atom are... and... respectively. MATCH THE COLUMN. C o l u m n-i C olumn-ii (A) Aufbau principle (p) Line spectrum in visible region (B) de broglie (q) Orientation of an electron in an orbital (C) Angular momentum (r) Poton (D) Hund's rule (s) = /mv (E) Balmer series (t) Electronic configuration (F) Planck's law (u) mvr. C o l u m n-i C olumn-ii (A) Catode rays (p) Helium nuclei (B) dumb-bell (q) Uncertainty principle (C) Alpa particles (r) Electromagnetic radiation (D) Moseley (s) p-orbital (E) Heisenberg (t) Atomic number (F) X-ray (u) Electrons 3. Frequency = f, Time period = T, Energy of n t orbit = E n, radius of n t orbit = r n, Atomic number = Z, Orbit number = n : C o l u m n-i C olumn-ii (A) f (p) n 3 (B) T (q) Z (C) E n (r) n (D) r (s) Z n

11 4. C o l u m n-i C olumn-ii (A) Lyman series (p) maximum number of spectral line observed = 6 (B) Balmer series (q) maximum number of spectral line observed = (C) In a sample 5 (r) nd line as wave number 8R 9 (D) In a single isolated H-atom for (s) nd line as wave number 3R 4 3 transition (t) total number of spectral line is 0 ASSERTION & RE ASON Tese questions contains, Statement I (assertion) and Statement II (reason). (A) Statement-I is true, Statement-II is true ; Statement-II is correct explanation for Statement-I. (B) Statement-I is true, Statement-II is true ; Statement-II is NOT a correct explanation for statement-i (C) Statement-I is true, Statement-II is false (D) Statement-I is false, Statement-II is true. Statement-I : Nodal plane of p x atomic orbital is yz plane. B e c a u s e Statement-II : In p x atomic orbital electron density is zero in te yz plane.. Statement-I : No two electrons in an atom can ave te same values of four quantum numbers. B e c a u s e Statement-II : No two electrons in an atom can be simultaneously in te same sell, same subsell, same orbitals and ave same spin. 3. Statement-I : p-orbital as dumb-bell sape. B e c a u s e Statement-II : Electrons present in p-orbital can ave one of tree values for 'm', i.e. 0, +, 4. Statement-I : Te ground state configuration of Cr is 3d 5 4s. B e c a u s e Statement-II : A set of exactly alf filled orbitals containing parallel spin arrangement provide extra stability. 5. Statement-I : Mass numbers of most of te elements are fractional. B e c a u s e Statement-II : Mass numbers are obtained by comparing wit te mass number of carbon taken as. 6. Statement-I : Limiting line in te balmer series as a wavelengt of 36.4 m. B e c a u s e Statement-II : Limiting lines is obtained for a jump of electron from n = to n = for Balmer series. 7. Statement-I : Te electronic configuration of nitrogen atom is represented as : not as B e c a u s e Statement-II : Te configuration of ground state of an atom is te one wic as te greatest multiplicity.

12 8. Statement-I : Te configuration of B atom cannot be s s 3. B e c a u s e Statement-II : Hund's rule demands tat te configuration sould display maximum multiplicity. 9. Statement-I : p orbitals do not ave sperical nodes. B e c a u s e Statement-II : Te number of sperical nodes in p-orbitals is given by (n ). 0. Statement-I : In Ruterford's gold foil experiment, very few particles are deflected back. B e c a u s e Statement-II : Nucleus present inside te atom is eavy.. Statement-I : Eac electron in an atom as two spin quantum numbers. B e c a u s e Statement-II : Spin quantum numbers are obtained by solving Scrodinger wave equation.. Statement-I : Tere are two sperical nodes in 3s-orbital. B e c a u s e Statement-II : Tere is no angular node in 3s-orbital. COMPREHENSION BASED QUESTIONS Compreensi on # Read te following rules and answer te questions at te end of it. Electrons in various suborbits of an orbit are filled in increasing order to teir energies. Pairing of electrons in various orbitals of a suborbit takes place only after eac orbital is alf-filled. No two electrons in an atom can ave te same set of quantum number.. Cr (Z = 4), Mn + (Z = 5), Fe + (Z = 6) and Co 3+ (Z = 7) are isoelectronic eac aving 4 electrons. Tus, (A) all ave configurations as [Ar] 4s 3d 5 (B) Cr and Mn + ave configurations as [Ar] 4s 3d 5 wile Fe + and Co 3+ ave configurations as [Ar]3d 5. (C) all ave configurations as [Ar] 3d 6 (D) all ave configurations as [Ar] 4s 3d 6. A compound of vanadium as a magnetic moment of.73 BM. Electronic configuration of te vanadium ion in te compound is : (A) [Ar] 4s 0 3d (B) [Ar] 4s 3d 3 (C) [Ar] 4s 3d 0 (D) [Ar] 4s 0 3d 5 3. Wic of tese ions are expected to be paramagnetic and coloured in aqueous solution? (A) Fe 3+, Ti 3+, Co 3+ (B) Cu +, Ti 4+, Sc 3+ (C) Fe 3+, Ni +, V 5+ (D) Cu +, Cu +, Fe + 4. Wile writing te following electronic configuration of Fe some rules ave been violated : I : Aufbau rule, II : Hund's rule III : Pauli's exclusion principle Ar 3d 4s (A) I, II (B) II, III (C) I, III (D) I, II, III

13 5. How many elements would be in te second period of te periodic table if te spin quantum number (m s ) could ave te value of,0,? (A) 8 (B) 0 (C) (D) 8 6. Te sub-sell tat arises after f sub-sell is called g sub-sell. (A) it contains 8 electrons and 9 orbitals (B) it corresponds to = 4 and first occurs in 5t energy level (C) a g-orbital can ave maximum of two electrons (D) all te above statements are true. MISCELLANEOUS TYPE QUESTION ANSWER KEY EXERCISE -3 Tr ue / False. F. F 3. T 4. T 5. T Fill in te Blanks. 3. nd 3. frequency or wavelengt , (4, 5, 6,...) Matc te Column. (A) t; (B) s ; (C) u ; (D) q ; (E) p; (F) r. (A) u ; (B) s ; (C) p ; (D) t ; (E) q ; (F) r 3. (A) q ; (B) p ; (C) q,r ; (D) r,s 4. (A) r ; (B) s; (C) p; (D) q Asserti on - Reason Questions. A. A 3. B 4. A 5. E 6. A 7. A 8. B 9. A 0. B. E. B Compreension Based Que st ions Compreension # :. (B). (A) 3. (A) 4. (D) 5. (C) 6. (D)

14 EXERCISE 04 [A] CONCEPTUAL SUBJECTIVE EXERCISE. How long would it take a radio wave of frequency sec to travel from mars to te eart, a distance of km?. Te energy levels of ypotetical one electron atom are sown below. 0 ev n = 0.50 ev n = 5.45 ev n = ev n = ev n = 5.6 ev n = (a) Find te ionisation potential of atom? (b) Find te sort wavelengt limit of te series terminating at n =? (c) (d) Find te wave no. of poton emitted for te transition made by te electron from tird orbit to first orbit? Find te minimum energy tat an electron will ave after interacting wit tis atom in te ground state, if te initial kinetic energy of te electron is (i) 6eV (ii) ev? 3. Suppose 0 7 J of ligt energy is needed by te interior of te uman eye to see an object. How many potons of green ligt ( = 550 nm) are needed to generate tis minimum amount of energy? 4. Find te number of potons of radiation of frequency s tat must be absorbed in order to melt one g ice wen te latent eat of fusion of ice is 330 J/g. 5. Te eyes of certain member of te reptile family pass a single visual signal to te brain wen te visual receptors are struck by potons of wavelengt 850 nm. If a total energy of J is required to trip te signal, wat is te minimum number of potons tat must strike te receptor? 6. Te wavelengt of a certain line in te Pascen series is nm. Wat is te value of n ig for tis line [R H = m ]. 7. Wavelengt of te Balmer H line (first line) is 6565 Å. Calculate te wavelengt of H (second line). 8. Calculate te Rydberg constant R if He + ions are known to ave te wavelengt difference between te first (of te longest wavelengt) lines of Balmer and Lyman series equal to 33.7 nm. 9. Calculate te energy emitted wen electrons of.0 g atom of ydrogen undergo transition giving te spectral line of lowest energy in te visible region of its atomic spectrum. 0. A poton aving = 854 Å causes te ionization of a nitrogen atom. Give te I.E. per mole of nitrogen in KJ.. Calculate energy of electron wic is moving in te orbit tat as its radius, Sixteen times te radius of first Bor orbit for H-atom Te electron energy in ydrogen atom is given by E n = ergs. Calculate te energy required n to remove an e completely from n = orbit. Wat is te largest wavelengt in cm of ligt tat can be used to cause tis transition.

15 3. Calculate te wavelengt in angstrom of poton tat is emitted wen an e in Bor orbit n = returns to te orbit n =. Te ionization potential of te ground state of ydrogen atom is.7 0 erg/atom. 4. Te velocity of e in a certain Bor orbit of te ydrogen atom bears te ratio : 75 to te velocity of ligt. Wat is te quantum no. "n" of te orbit and te wave no. of te radiation emitted for te transition form te quantum state (n + ) to te ground state. 5. A doubly ionised litium atom is ydrogen like wit atomic number Z = 3. Find te wavelengt of te radiation required to excite te electron in Li + from te first to te tird Bor orbit. 6. Estimate te difference in energy between I and II Bor Orbit for a ydrogen atom. At wat minimum At. no. a transit ion from n = to n = energy level would re sult i n te emission of X-rays w it = m? Wic ydrogen like species does tis At. no. correspond to: 7..8 g atoms of ydrogen are excited to radiations. Te study of spectra indicates tat 7% of te atoms are in 3 rd energy level and 5% of atoms in n d energy level and te rest in ground state. If I.P. of H is.7 0 erg. Calculate. (i) (ii) No. of atoms present in III & II energy level. Total energy evolved wen all te atoms return to ground state. 8. One mole He + ions are excited. Spectral analysis sowed existence of 50% ions in 3 rd orbit, 5% in nd and rest in ground state. Calculate total energy evolved wen all te ions return to te ground state. 9. Te energy of an excited H-atom is 3.4 ev. Calculate angular momentum of e. 0. Te vapours of Hg absorb some electrons accelerated by a potential difference of 4.5 volt as a result of it ligt is emitted. If te full energy of single incident e is supposed to be converted into ligt emitted by single Hg atom, find te wave no. of te ligt.. Te ydrogen atom in te ground state is excited by means of monocromatic radiation of wavelengt x A 0. Te resulting spectrum consists of 5 different lines. Calculate te value of x.. If te average life time of an excited state of H atom is of order 0 8 sec, estimate ow many orbits an e makes wen it is in te state n = and before it suffers a transition to n = state. 3. Calculate te frequency of e in te first Bor orbit in a H-atom. 4. A single electron orbits around a stationary nucleus of carge +Ze were Z is a constant from te nucleus and e is te magnitude of te electric carge. Te ydrogen like species required 47. ev to excite te electron from te second Bor orbit to te tird Bor orbit. Find - (i) (ii) te value of Z give te ydrogen like species formed. te kinetic energy and potential energy of te electron in te first Bor orbit. 5. A stationary He + ion emitted a poton corresponding to a first line of te Lyman series. Te poton liberated a potoelectron from a stationary H atom in ground state. Wat is te velocity of potoelectron? 6. To wat series does te spectral lines of atomic ydrogen belong if its wave number is equal to te difference between te wave number of te following two lines of te Balmer series 486. and 40. nm. Wat is te wavelengt of tis?

16 7. A particle of carge equal to tat of an electron and mass 08 times te mass of te electron moves in a circular orbit around a nucleus of carge +3e. Assuming tat te Bor model of te atom is applicable to tis system, (a) derive an expression for te radius of te n t bor orbit, (b) find te value of n for wic te radius of te orbit is approximately te same as tat of te first Bor orbit for te ydrogen atom, and (c) find te wavelengt of te radiation emitted wen te revolving particle jumps from te tird orbit to te first. 8. A neutrons breaks into a proton and an electron. Tis decay of neutron is accompanied by release of energy. Assuming tat 50% of te energy is produced in te form of electromagnetic radiation, wat will be te frequency of radiation produced. Will tis poton be sufficient to cause ionization of Aluminium. In case it is able to do so wat w ill be te energy of te electron ejected from te Alumi num atom. IE of Al = 577 kj/mol. 9. Calculate te tresold frequency of metal if te binding energy is kj mol of electron Calculate te binding energy per mole wen tresold wavelengt of poton is 40 nm. 3. A metal was irradiated by ligt of frequency s. Te potoelectron produced ad its KE, times te KE of te potoelectron wic was produced wen te same metal was irradiated wit a ligt of frequency s. Wat is work function? 3. U.V. ligt of wavelengt 800 A & 700 A falls on ydrogen atoms in teir ground state & liberates electrons wit kinetic energy.8 ev and 4 ev respectively. Calculate planck's constant A potential difference of 0 kv is applied across an X-ray tube. Find te minimum wavelengt of X-ray generated Te K.E. of an electron emitted from tungsten surface is 3.06 ev. Wat voltage would be required to bring te electron to rest. 8kT 3 5. Wat is de-broglie wavelengt of a He-atom in a container at room temperature. Use U avg. m 3 6. Troug wat potential difference must an electron pass to ave a wavelengt of 500 A A proton is accelerated to one tent of te velocity of ligt. If its velocity can be measured wit a precision ± %. Wat must be its uncertainty in position? 3 8. To wat effective potential a proton beam be subjected to give its protons a wavelengt of 0 0 m Calculate te number of excange pairs of electrons present in configuration of Cu according to Aufbau principle considering 3d orbitals He atom can be excited to s p by = nm. If lowest excited state for He lies 4857 cm below te above. Calculate te energy for te lower excitation state. 4. A certain dye absorbs 4530 A and fluoresence at 5080 A tese being wavelengts of maximum absorption tat under given conditions 47% of te absorbed energy is emitted. Calculate te ratio of te no. of quanta emitted to te number absorbed. 4. Te reaction between H and Br to form HBr in presence of ligt is initiated by te poto decomposition of Br into free Br atoms (free radicals) by absorption of ligt. Te bond dissociation energy of Br is 9 kj/mole. Wat is te longest wavelengt of te poton tat would initiate te reaction? 4 3. Te quantum yield for decomposition of HI is 0.. In an experiment 0.0 moles of HI are decomposed. Find te number of potons absorbed.

17 4 4. Calculate te wavelengt of te radiation tat would cause poto dissociation of clorine molecule if te Cl Cl bond energy is 43 kj/mol Te dissociation energy of H is kj/mol. If H is exposed to radiant energy of wavelengt 53.7 nm, wat % of radiant energy will be converted into K.E? 4 6. Iodine molecule dissociates into atoms after absorbing ligt of 4500 A 0 If one quantum of radiation is absorbed by eac molecule, calculate te K.E. of iodine atoms. (Bond energy of I = 40 kj/mol) 4 7. X-rays emitted from a copper target and a molybdenum target are found to contain a line of wavelengt.85 nm attributed to te K line of an impurity element. Te K lines of a copper (Z = 9) and molybdenum (Z = 4) ave wavelengt 5.4 nm and 7. nm respectively. Using Moseley's law, / = a (Z b). Calculate te atomic number of te impurity element Wat is de-broglie wavelengt associated wit an e accelerated troug P.D. = 00 kv? 4 9. Calculate te de-broglie wavelengt associated wit motion of eart (mass kg) orbiting around te sun at a speed of m/s A base ball of mass 00 g is moving wit velocity 30 0 cm/s. If we can locate te base ball wit error equal in magnitude to te of te ligt used (5000 Å), ow will te uncertainty in momentum compared wit te total momentum of base ball? 5. An electron as a speed of 40 m/s, accurate up %. Wat is te uncertainty in locating position? CONCEPTUAL SUBJECTIVE EXERCISE ANSWER KEY E X E RC ISE - 4( A) sec. (a) 5.6 ev (b) 33.9 nm, (c) m (d) (i) electron will not interact (ii) 0.7 ev 3. 8 potons A m J/mol kj/mol Joules ergs, cm 3. 0 A 4. ; cm A ev, Z= atoms, atoms, kj J 9. / m. 938 A Hz 4. (i) Z = 5, (ii) 340 ev, 680 ev cm/sec 6. Brackett ; cm n 7. r n = 4K 3e 08m e ; n = 5 ; 55. pm Hz, yes, J s kj/mol kj/mol Js A V A volt m volts J A m % Joules pm m m

18 EXERCISE 04 [B] BRAIN STORMING SUBJECTIVE EXERCISE. To wat series does te spectral lines of atomic ydrogen belong if its wave number is equal number is equal to te difference between te wave numbers of te following two lines of te Balmer series 486. and 40. nm? Wat is te wavelengt of tis line?. Energy required for te excitation of H-atom its ground state to te nd excited state is.67 times smaller tan dissociation energy of H (g). If H (g) placed in.0 litre flask at 7 Cand.0 bar is to be excited to teir nd excited state, wat will be te total energy consumption? 3. Find te quantum number 'n' corresponding to te excited state of He + ion if on transition to te ground state tat ion emits two potons in succession wit wavelengts 08.5 and 30.4 nm. 4. A gas of identical H-like atom as some atoms in te lowest (ground) energy level A and some atoms in a particular upper (excited) energy level B and tere are no atoms in any oter energy level. Te atoms of te gas make transition to a iger energy level by absorbing monocromatic ligt of poton energy.7 ev. Subsequently, te atoms emit radiation of only six different potons energies. Some of te emitted potons ave energy.7 ev. Some ave more and some ave less tan.7 ev. (a) Find te principal quantum number of initially excited level B. (b) Find te ionisation energy for te gas atoms. (c) Find te maximum and te minimum energies of te emitted potons. 5. A ydrogen like atom (atomic number Z) is in a iger excited state of quantum number n. Tis excited atom can make a transition to te first excited state by successively emitting two potons of energies 0.0 ev and 7.00 ev respectively. Alternatively, te atom from te same excited state can make a transit ion to te second excited state by successively emit ting two potons of energy 4.5 ev and 5.95 ev respectively. Determine te values of n and z (ionisation energy of ydrogen atom = 3.6 ev). 6. Hydrogen atom in its ground state is excited by means of monocromatic radiation of wavelengt 975 A. How many different lines are possible in te resulting spectrum? Calculate te longest wavelengt amongst tem. 7. An alpa particle after passing troug a potential difference of 0 6 volt falls on a silver foil. Te atomic number of silver is 47. Calculate (i) te K.E. of te alpa-particle at te time of falling on te foil. (ii) K.E. of te -particle at a distance of m from te nucleus, (iii) te sortest distance from te nucleus of silver to wic te -particle reaces. ke 8. Suppose te potential energy between electron and proton at a distance r is given by 3r teory to obtain energy of suc a ypotetical atom. 3. Use Bor's 9. An energy of 68 ev is required to excite a ydrogen like atom from its second Bor orbit to te tird. Te nuclear carge is Ze. Find te value of Z, te kinetic energy of te electron in te first Bor orbit and te wavelengt of te radiation required to eject te electrons from te first Bor orbit to infinity. 0. Te ionisation energy of a H-like Bor atom is 4 Rydbergs. (i) Wat is te wavelengt of radiation emitted wen te e jumps from te first excited state to te ground state? (ii) Wat is te radius of first Bor orbit for tis atom? [ Rydberg = J]. Poton aving wavelengt.4 nm was allowed to strike a metal plate aving work function 5 ev. Calculate te -

19 (a) (b) (c) Maximum kinetic energy of potoelectrons emitted in ev. Wavelengt of electron wit maximum kinetic energy in A. Calculate te uncertainity in wavelengt of emitted electron, if te uncertainity in te momentum is kg m/sec.. Electron present in single electron species jumps from energy level 3 to. Emitted potons wen passed troug a sample containing excited He + ion causes furter excitation to some iger energy level (Given E n = 3.6 Z n ) : Determine. (i) Atomic number of single electron species. (ii) Principal quantum number of initial excited level & iger energy of He + 3. Te angular momentum of an electron in a Bor's orbit of H-atom is kg-m /sec. Calculate te wave number in terms of Rydberg constant (R) of te spectral line emitted wen an electron falls from tis level to te ground state. (Use = Js). BRAIN STORMING SUBJECTIVE EXERCISE ANSWER KEY EXERCI SE -4 ( B ). n = 4, n = 6, cm..8 kj 3. n = 5 4. (a) n =, (b) 4.4 ev, (c) 3.5eV, 0.7eV 5. n = 6, Z = 3 6. six, 8800 A n J,. 0 3 J, m 8. E = 384m K e ; ev, 5.8 A A, cm. (a) 75 ev ; (b).44 A ; (c) 0 4 m. (i) Z = (ii) For He + ion tis energy corresponds to excitation from to R 8 9

20 EXERCISE - 05 [A] JEE-[MAIN] : PREVIOUS YEAR QUESTIONS. An atom as a mass of 0.0 kg and uncertainty in its velocity is m/s ten uncertainty in position is ( = Js) [AIEEE 00] () m () cm (3) m (4) m. Energy of H- atom in te ground state is 3.6 ev, Hence energy in te second excited state is- [AIEEE 00] () 6.8 ev () 3.4 ev (3).5 ev (4) 4.3 ev 3. Uncertainty in position of a particle of 5 g in space is 0 5 m. Hence uncertainty in velocity (ms ) is (Planck's constant = Js) [AIEEE-00] (). 0 8 () (3) (4) Te orbital angular momentum for an electron revolving in an orbit is given by ( ). for an s-electron will be given by (). () +. (3) zero (4). Tis momentum [AIEEE-003] 5. Te number of d-electrons retained in Fe + (At. no. of Fe = 6) ion is : [AIEEE-003] () 6 () 3 (3) 4 (4) 5 6. Te de Broglie wavelengt of a tennis ball of mass 60 g moving wit a velocity of 0 metres per second is approximately : [AIEEE 003] () 0 5 metres () 0 33 metres (3) 0 3 metres (4) 0 6 metres 7. In Balmer series of lines of ydrogen spectrum, te tird line from te red end corresponds to wic one of te following inter-orbit jumps of te electron for Bor orbits in an atom of ydrogen? () 5 () 3 (3) 5 (4) 4 8. Wic of te following sets of quantum number is correct for an electron in 4f orbital? [AIEEE-004] [AIEEE-003] () n = 3, l =, m =, s = + () n = 4, l = 4, m = 4, s = (3) n = 4, l = 3, m = +, s = + (4) n = 4, l = 3, m = + 4, s = + 9. Consider te ground state of Cr atom (Z = 4). Te numbers of electrons wit te azimutal quantum numbers, l = and are, respectively () 6 and 5 () and 5 (3) 6 and 4 (4) and 4 [AIEEE-004] 0. Te wavelengt of te radiation emitted, wen in a ydrogen atom electron falls from infinity to stationary state, would be (Rydberg constant = m ) : () nm () 9 nm (3) 406 nm (4) 9 nm. Wic one of te following sets of ions represents te collection of isoelectronic species? [AIEEE-004] () Na +, Mg +, Al 3+, Cl () Na +, Ca +, Sc 3+, F (3) K +, Cl, Mg +, Sc 3+ (4) K +, Ca +, Sc 3+, Cl [AIEEE-004]. In a multi-electron atom, wic of te following orbitals described by te tree quantum members will ave te same energy in te absence of magnetic and electric fields? [AIEEE-005] (A) n =, l = 0, m = 0 (B) n =, l = 0, m = 0 (C) n =, l =, m = (D) n = 3, l =, m = (E) n = 3, l =, m = 0 () (D) and (E) () (C) and (D) (3) (B) and (C) (4) (A) and (B)

21 3. Of te following sets wic one does not contain isoelectronic species? [AIEEE-005] () 3 BO, CO, NO () SO, CO, NO (3) CN, N, C (4) 3 PO, SO, ClO Wic of te following statements in relation to te ydrogen atom is correct? [AIEEE-005] () 3s, 3p and 3d orbitals all ave te same energy () 3s and 3p orbitals are of lower energy tan 3d orbitals (3) 3p orbital is lower in energy tan 3d orbital (4) 3s orbitals is lower in energy tan 3p orbital 5. According to Bor's teory angular momentum of electron in 5 t sell is :- [AIEEE-006] ().0 / () 0 / (3).5 / (4) 5 / 6. Uncertainty in te position of an electron (mass = Kg) moving wit a velocity 300 ms, accurate upto 0.00%, will be :- ( = Js) [AIEEE-006] () m ().9 0 m (3) m (4) 9. 0 m 7. Wic of te following sets of quantum numbers represents te igest energy of an atom? [AIEEE-007] () n = 3, l =, m =, s = +½ () n = 3, l =, m =, s = +½ (3) n = 4, l = 0, m =0, s = +½ (4) n = 3, l = 0, m =0, s = +½ 8. Wic one of te following constitutes a group of te isoelectronic species? [AIEEE-008] () C,O,CO,NO NO,C,CN,N CN,N,O,C () (3) (4) N,O,NO,CO 9. Te ionziation entalpy of ydrogen atom is.3 x 0 6 J mol. Te energy required to excite te electron in te atom from n = to n = is [AIEEE-008] () 8.5 x 0 5 J mol () 6.56 x 0 5 J mol (3) 7.56 x 0 5 J mol (4) 9.84 x 0 5 J mol 0. In an atom, an electron is moving wit a speed of 600 m/s wit an accuracy of 0.005%. Certainity wit wic te position of te electron can be located is ( = kg m s, mass of electron, e m = kg):- () m () m (3) m (4) m [AIEEE-009]. Calculate te wavelengt (in nanometer) associated wit a proton moving at ms (Mass of proton = kg and = Js) :- [AIEEE-009] ().5 nm () 4.0 nm (3) 0.03 nm (4) 0.40 nm. Te energy required to break one mole of Cl Cl bonds in Cl is 4 kj mol. Te longest wavelengt of ligt capable of breaking a single Cl Cl bond is (C = ms and N A = mol ) [AIEEE-00] () 494 nm () 594 nm (3) 640 nm (4) 700 nm 3. Ionisation energy of He + is J atom. Te energy of te first stationary state (n = ) of Li + is:- () J atom () J atom [AIEEE-00] (3) J atom (4). 0 5 J atom 4. A gas absorbs a poton of 355 nm and emits at two wavelengts. If one of te emissions is at 680 nm, te oter is at :- [AIEEE-0] () 743 nm () 58 nm (3) 035 nm (4) 35 nm 5. Te frequency of ligt emitted for te transition n = 4 to n = of He + is equal to te transition in H atom corresponding to wic of te following :- [AIEEE-0] () n = 3 to n = () n = to n = (3) n = 3 to n = (4) n = 4 to n = 3 6. Te increasing order of te ionic radii of te given isoelectronic species is :- [AIEEE-0] () K +, S, Ca +, Cl () Cl, Ca +, K +, S (3) S, Cl, Ca +, K + (4) Ca +, K +, Cl, S

22 7. Te electrons identified by quantum numbers n and :- [AIEEE-0] (a) n = 4, = (b) n = 4, = 0 (c) n = 3, = (d) n = 3, = Can be placed in order of increasing energy as () (a) < (c) < (b) < (d) () (c) < (d) < (b) < (a) (3) (d) < (b) < (c) < (a) (4) (b) < (d) < (a) < (c) PREVIOUS YEARS QUESTIONS ANSWER KEY EXERCISE-5 [A] Q u e A n s Q u e A n s

23 EXERCISE - 05 [B] JEE-[ADVANCED] : PREVIOUS YEAR QUESTIONS. Ruterfords experiment, wic establised te nuclear model of atom, used a beam of : (A) - particles, wic impinged on a metal foil and get absorbed. [JEE 00] (B) - rays, wic impinged on a metal foil and ejected electron. (C) Helium atoms, wic impinged on a metal foil and got scattered. (D) Helium nuclie, wic impinged on a metal foil and got scattered.. Te magnetic moment of cobalt of te compund Hg[Co(SCN) 4 ] is [Given : Co + ] [JEE 004] (A) 3 (B) 8 (C) 5 (D) 4 3. Te radius of wic of te following orbit is same as tat of te first Bor s orbit of ydrogen atom? (A) He + (n = ) (B) Li + (n = ) (C) Li + (n = 3) (D) Be 3+ (n = ) [JEE 004] 4. (a) Te Scrodinger wave equation for ydrogen atom is [ II T-0 04 ] 3/ r s / 4( ) a a 0 r / a e 0 0 Were a 0 is Bor's radius. Let te rdial node in s be at r 0. Ten find r 0 in terms of a 0. (b) A base ball aving mass 00 g moves wit velocity 00 m/s. Find out te value of wavelengt of base ball. 5. (a) Calculate velocity of electron in first Bor orbit of ydrogen atom (Given r = a 0 ) [ II T-0 05 ] (b) Find de-broglie wavelengt of te electron in first Bor orbit. (c) Find te orbital angular momentum of p-orbital in terms of / units. 6. Given in ydrogenic atom r n, V n, E, K n stand for radius, potential energy, total energy and kinetic energy in n t orbit. Find te value of U,v,x,y. [JEE 006] (A) U = V K n n (P) (B) r n E x (Q) (C) r n Z y (R) (Z = Atomic number) (D) v = (Orbital angular momentum of electron (S) 0 in its lowest energy )

24 7. Matc te entries in Column I wit te correctly related quantum number(s) in Column II. Indicate your answer by darkening te appropriate bubbles of te 4 4 matrix given in te ORS. [JEE 008] Column I Column II (A) Orbital angular momentum of te (P) Principal quantum number electron in a ydrogen-like atomic orbital (B) A ydrogen-like one-electron wave (Q) Azimutal quantum number function obeying Pauli principle (C) Sape, size and orientation of ydrogen (R) Magnetic quantum number like atomic orbitals (D) Probability density of electron at te nucleus (S) Electron spin quantum number in ydrogen-like atom (A) Paragrap for questions 8 to 0 [JEE 00] Te ydrogen-like species Li + is in a sperically symmetric state S wit one radial node. Upon absorbing ligt te ion undergoes transition to a state S. Te state S as one radial node and its energy is equal to te ground state energy of te ydrogen atom. 8. Te state S is :- (A) s (B) s (C) p (D) 3s 9. Energy of te state S in units of te ydrogen atom ground state energy is :- (A) 0.75 (B).50 (C).5 (D) Te orbital angular momentum quantum number of te state S is :- (A) 0 (B) (C) (D) 3. Te maximum number of electrons tat can ave principal quantum number, n=3, and spin quantum number, m s = /, is [JEE 0]. Te work function () of some metals is listed below. Te number of metals wic will sow potoelectric effect wen ligt of 300 nm wavelengt falls on te metal is :- [JEE 0] Metal Li Na K Mg Cu Ag Fe Pt W (ev) Te kinetic energy of an electron in te second Bor orbit of a ydrogen atom is [a 0 is Bor radius] [JEE 0] (A) 4 ma 0 (B) 6 ma 0 (C) 3 ma 0 (D) 3 ma 0 PREVIOUS YEARS QUESTIONS. (D). (C) 3. (D) 4. (a) r 0 = a 0 (b) Å 5. (a) m/s (b) 3.3 Å (c) ANSWER KEY. π 6. (A) Q, (B) P, (C) R, (D) S 7. (A) Q,R (B) P, Q, R,S (C) P, Q, R (D) P, Q 8. (B) 9. (C) 0. (B) (C) EXERCISE-5 [B]