Structure of Atom

Structure o f Atom JEE Advanced/ IIT-JEE

The mass of a hydrogen atom is ............. kg. (1982 - 1 Mark)

Isotopes of an element differ in the number of: ............. in their nuclei. (1982 - I Mark) When there are two electrons in the same orbital, they have ............. spms. (1982 - 1 Mark) Elements of the same mass number but of different atomic numbers are h o w n as : ............... (1983 - 1 Mark) The uncertainty principle and the concept of wave nature of matter were proposed by ............... and ............... respectively. (Heisenberg, Schrodiiger, Maxwell, de Broglie)

(1988 - 1 Mark) The light radiations with discrete quantities of energy are called ................. (1993 - 1 Mark) Wave functions of electrons in atoms and molecules are called ................ (I993 - 1 Mark) The 2px, 2py and 2p. orbitals of atom have identical shapes but differ in their ................ (1993 - 1 Mark) The outermost electronic configuration.of Cr is ................ I (1994 - 1 Mark)

1 . The outer electronic configuration of the ground state chromium atom is 3d'4s2. (1982 - 1 Mark)

2. Gamma rays are electromagnetic radiations of wavelengths of 1 0-6 cm to 1 0-5 cm. (1983 - 1 Mark)

3. The energy of the electron in the 3d-orbital is less than that in the 4s-orbital in the hydrogen atom. (1983 - 1 Mark)

4. The electron density in theXYplane in 3d orbital is x - Y

zero. (I986 - I Mark) 5. In a given electric field, P-particles are deflected more than

a-particles in spite of a-particles having larger charge. 11993 - 1 Mark)

1. The number of neutrons in dipositive zinc ion with mass number 70 is (1 9 79) (a) 34 @) 36 (4 38 (d) 40

Rutherford's experiment on scattering of a-particles showed for the fust time that the atom has (1981 - 1 Mark) (a) electrons (h) protons (c) nucleus (d) neutrons -Any p-orbital can accommodate upto (1983 - I Mark) (a) four electrons @) six electrons (c) two electrons with parallel spins (d) two electrons with dpposite spins The principal quantum number of an atom is related to the

(1983 - 1 Mark) (a) size of the orbital @) spin angular momentum (c) orbital angular momentum (d) orientation ofthe orbital in space Rutherford's scattering exljeriment is related to the size of the (1983 - 1 Mark) (a) nucleus @) atom (c) : electron (d) neutron The increasing order '(lowest first) f o ~ the values of elm (chargelmass) for electron (e), proton (p), neutron (n) and alpha particle (a) is : . . (1984 - 1 Mark) (a)' e,p, n;a @) n,p, e, a '. , (c) n , ~ , a, e (d) n, a,p, e Correct set of four quantum numbers for the vaience (outermost) electron ofrubidium (Z=37) is :

(1984 - 1 Mark) (a) 5,0,0,+% @) 5, 1,0,+% (c) 5, I , I,+% (d) 6,0,0,+% Whikh electronic level would allow the hydrogen atom to absorb a photon but not to emit a photon?

(1984 - I Mark) (a) 3s @) 2~ ( 9 ' 2s (d) 1s Bohr model can explain : (1985 - 1 Mark) (a) the spectrum of hydrogen atom only (b) spectrum of an atom or ion containing one electron

only (c) the spectrum of hydrogen molecule (d) the solar spechum , . The radius of an atomic nucleus is' of the order of:

(I985 - 1 Mark) (a) 10-lOcm~ @) 10-'~cm (c) 10-Is cm (d) 104cm

TransWeb Educational Services Pvt. LtdB 147,1st Floor, Sec-6, NOIDA, UP-201301

Website:www.askiitians.com Email. [email protected]:0120-4616500 Ext - 204

Topic-wise Solved Papers - CHEMISTRY 11. Electromagnetic radiation with maximum wavelength is :

(1 985 - 1 Mark) (a) ultraviolet . (b) radiowave; (c) x-ray. (d) infrared

12. Rutlierford's alpha particle scattering experiment eventually led to the conclusion that : (1986,- 1 Mark) (a) mass and energy are related (b) . electrons occupy space around the nucleus (c) neutrons are buried deep in the nucleus (d) the point of impact with matter ..can be. precisely

determined. 13. Which one of~the following sets of quantum numbers

represents an impossible arrangement? (1986 - 1 Mark) I n

ms

(a) 3 2 -2 . % , , , _(b) 4 0 0 % (c) . 3. 2 -3 % ; ( 4 5 3 0 . -%

14. The ratio of the energy of a photon of 2000.A wavelength. radiation to that of 4000A radiation is : (1986 - I Mark) (a) '/. (b) 4 (c) % ; (d): 2

15. The triad of nuclei that is isotonic is (1988 - I Mark)

14 14 17 (c) ,5', 7 N , gF 14 (d) ,c, ';N, ';F 1 16. The wavelength of a spectral line for an electronic transition

is inversely related to : (1988 - 1 Mark) (a) the number of electrons undergoing the transition (b) the nuclear charge ofthe atom (c) the difference in the energy of the energy levels

involved in the transition (d) the velocity of the electron undergoing the transition.

17. , The orbital diagram in which the Aufbauprinciple is violated is : (1988 - I Mark)

2s ZP

18. The outermost electronic configuration of the most electtonegative element is (1988 - 1 Mark) (a) ns2 np3 (b) ns2 np4 (c) ns2 np5 (d) ns2 np6

19. The correct ground state electronic configuration of chromium atom is : (I989 - 1 Mark) (a) [Ar] 3dS 4s' (b) [Arl3&43 (c) [Ar] 3 8 4s0 (d) [Ar] 4dS 4s'

20. The correct set of quantum numbers for the unpaired electron of chlorine atomis : (1989 - IMark)

n 1 m (aj ' 2' .I. o (b) 2 1 1

1 (c) 3 1 (d), 3 - 0 0

21. Which of the following does not chgacterise X-rays? (1992 -.I Mark)

(a) ' The radiation can ionise gases A . . (b) It causes ZnS to fluorescence (c) Deflected by electric and magnetic fields (d) Have wavelengths shorter than ultraviolet rays

22. Which of the following relates to photons both as wave motion and as a stream of particles? (1992 -I-Mark) (a) Inference (b) &=mcZ. (c) Diffraction (d) E = hv

23. A 3p orbital has : (1 995s) (a) two non sphkrical nodes (b) two spherical nodes (c) one spherical & one non ~~herical'node (d) one spherical and two non spherical nodes ' .

24. . The orbital angular momentum of an electron in 2s orbital i s (1996 - 1 Mark)

- .

(b) Zero

25. The first use of quantum theory to explain the structure of atom was made by (1997C- 1 Mark) (a) Heisenberg (b) Bohr (c) Planck (d) Einstein

26. For a d-electron, the orbital angular momentum is (1997- 1 Mark)

-(c) (h12x) . - (d) 2(h/2n) 27. The electrons, identified by quantum numbers n and I, (i) n

=4,l=l,(ii)n=4,l=0,(iii)n=3,1-2,and(iv)n=3,l=i ' . can be placed in order of increasing energy, from the lowest

to highest, as (1999 - 2 Marks) a ( v < (i) < ( i ) < (i) (b) (ii) < (iv) < (i) C(iii) (c)' (i) < (iii) < (ii) < (iv) (d) (iii)

30. The wavelength associated with a golfball weighing200 g and moving at a speed of 5 m/h is of the order (ZOOIS) (a) 10-iOm (b) 10-20m (c) 10-"m (d) 10AOm

31; The quantum numbers +1/2 and -112 for the electron spin represent (2001s) (a) rotation ofthe electron in clockwise and anticlockwise

direction respectively @) rotation ofthe electron in anticlockwise and clockwise

direction respectively (c) magnetic moment of theelectron pointing up and.down

, . . , respectively , , (d) two quantum mechanical spin states which have no

classical analogue 32. Rurtherford's experiment, which established the nuclear

model ofthe atom, used a beam of (2002s) . .

(a) I3 -particles, which impinged on a metal foil and got ,; absorbed . . ' . ..

@) 't -rays, which impinged on a metal foil and ejected electrons

(c) helium atoms, which impinged on a metal foil and got scattered

(d) heliumnuelei, which impinged on a metal foil and got , .

. .

scattered 33. -1fthenitrogen atom has electronic configuration Is7, $ would

have energy lower than that,of the normal ground state configuration 1 s ~ 2 s ~ 2 ~ ' , ' because the electrons would be closer to the nucleus. Yet Is7 is not observed because i i violates. . . , (2002s) (a)- Heisenberg uncertainty principle

. (b) Hund's rule (c) Pauli exclusion principle (d) Bohr postulate of stationary orbits

34. The radius of which ofthe following orbit is same as that of the first BOhr's orbit of hydrogen atom? (200.Is) (a) Het (n=2) (b) ' ~ i ~ + (n = 2)

. (c) Li2+ (n= 3) (d) Be3+ (n = 2) 35. . Thenumber of radial nodes of 3s and 2p orbitals are

respectively (2005s) (a) 2,O (b) 0,2 ( 4 1,2 (d) 2, 1

36. Given that the abundances of isotopes 54Fe, 5 6 ~ e and 57 Fe are 5%, 90% and S%, respectively, the atomic mass of Fe is (a) 55.8s @) 55.95 (2009s) (c) 55.75 (d) 56.05

37; The kinetic energy of an electron in the second ~ b h r orbit of ' a hydrogen atom is [ao is Bohr radius] : (2012)

1. An isqtone of z ; ~ e is : (1984 - 1 Mark)

2. Many elements have non-integral atomic masses because : (1984 - 1 Mark)

(a) they have isotopes (b) their isotopes have non-integral masses (c) their isotopes have different masses (d) the.constitutents, neutrons, protons and klectrons,

combine to give fractional masses 2.- When alpha particles are sent through a thin metal foil, most

of them go straight through the foil because : . ' 11984 - 1 Mark)

(a) alpha particles are much heavier than electrons ., (b) alpha particles are positively chirged

(c) most part of the atom is emptyspace (d) alpha particle move with high velocity .. ,

4. The sum ofthe numbe;ofneutrons and proton in the isotope of hydrogen is : . , (1986 - 1 Mark) ' (a) 6 .@) 2

, . (c) 4 (dl. 3 5. The energy of an electron in the first Bohr orbit ofH atomis

-13.6 eV. The possible energy value(s) ofthe excited state(s) for electrons in BO& orbits of hydrogen is (are)

(1998 - 2 Marks) (a) -3.4eV (b) -4.2 eV (c) -6,SeV (d) -1.5eV

6. Which of the following satement(s) iS (arejcoriect? (1998 - 2 Marks)

(a) The electrbnic configuration of ~r is [Ar] 384s'. (Atomic Number ofCr = 24)

(b) The magnetic quantum number may have a negative , . value.

(c) In silver atom, 23 electrons havea spin of one type and 24 ofthe opposite type. (Atomic Number ofAg = 47)

. (d) The oxidation state of nitrogen in HN3 is -3. 7. Decrease in atomic number is observed during

. . (1998 - 2 Marks) (a) alpha emission (b) beta emission (c) : positron emission (d) electron capture. . .

8. Ground state electronic configuration of nitrogen atom can be represented by (1999 - 3 Marks)



I C-30 Topic-wise Solved Papers - CHEMISTRY I 1 11. Find out the number of waves made by a Bohr electron in one complete revolution in its 3rd orbit. (1994 - 3 Marks)

Naturally occurring boron co~.~is ts of two isotopes whose atomic weights are 10.01 and 11.01. The atomic weight of natural boron is 10.81. Calculate the percentage of each isotope in natural boron. (1978) Account for the foliowing. Limit your answer to two sentences: (1979) Atomic weights of most of the elements are fractional. The energy ofthe electron in the second and the third Bohr's orbits of the hydrogen atom is -5.42 x erg and -2.41 x 10-l2 erg re'spectively. Calculate the wavelength of the emitted radiation when the electron drops from the third to the second orbit. (I981 - 3 Marks) Calculate the wavelength in Angstrom ofthe photon that is emitted when an electron in the Bohr orbit, n = 2 retuins to the orbit, n = 1 in the hydrogen atom. The ionization potential of the ground state hydrogen atom is 2.17 x lo-" erg per atom. (1982 - 4 Marks) The electron energy in hydrogen atom is given by E=(-21.7 x 10-12)ln2 ergs. Calculatethe energy required to remove an electron completely from then = 2 orbit. What is the longest wavelength (in cm) of light that can be used to cause this transition? (1984 - 3 Marks) Give reasons why the ground state outermost electronic configuration of silicon is : (1985 - 2 Marks)

.IfltlI and not (t.11 7. What is the maximum number of electrons that may be

present in all the atomic orbitals with principal quantum number 3 and azimuthal quantum number 2?

(1985 - 2 Marks) 8. According to Bohr's theory, the electronic energy of

hydrogen atom in the nth Bohr's orbit is given by

-21 .76~10- '~ ' E" = 2 J. Calculate the longest wavelength n of light that will be needed to remove an electron from the third Bohr orbit of the Hef ion. (1990 - 3 Marks)

9. Estimate the difference in energy between 1st and 2nd Bohr orbit for a hydrogen atom. At what minimum atomic number, a transition from n = 2 to n = 1 energy level would result in the emission of X-rays with h=3,0x10-*m? Which hydrogen atom-like species does this atomic number correspond to ? (I993 - 5 Marks)

10. What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He+ spectrum? (1993 - 3 Marks)

12. Iodine molecule dissociates into atoms after absorbing light of 4500 A . If one quantum of radiation is absorbed by each molecule, calculate the kinetic energy of iodine atoms. (Bond energy of I, = 240 kJ mol-') (1995 - 2 Marks)

13. Calculate the wave number for the shortest wavelength transition in the Balmer series of atomic hydrogen.

(1996 - 1 Mark) Consider the hydrogen atom to be a proton embedded in a cavity ofradiu. a,, (Bohr radius) whose charge is neutralised by the addition of an electron to the cavity in vacuum, infinitely slowly. Estimate the average total energy of an electron in its ground state in a hydrogen atom as the woik done in the above neutralisation process. Also, if the magnitude of the average kinetic energy is half the magnitude of the average potential energy, find the average potential energy.

(1996 - 2 Marks) 15. With what velocity should an a-particle travel towards the

nucleus of a copper atom so as to arrive at a distance lo-" metre from the nucleus of the copper atom?

(1997C- 3 Marks) 16. An electron beam can undergo diffraction by crystals.

Through what potential should a beam of electrons be accele~a~ed so that its wavelength becomes equal to 1.54 A.

(1997C - 2 Marks) 17. Calculate the energy required to excite one litre ofhydrogen,

gas at 1 atm and 298 K to the fust excited state of aiomic hydrogen. The energy for the dissociation of H-H bond is 436kJmoI-'. (2000 - 4 Marks)

18. Wavelength ofhigh energy transition ofH-atoms is 9 1.2nm. Calculate the corresponding wavelength of He atoms.

(2003 - 2 Marks) 19. The Schrodinger wave equation for hydrogen atom is

(2004 - 2 Marks)

Where a. is-Bohr's radius. If the radial node in 2s be at ro, then find ro in terms of a,. A ball of mass 100 g is moving with 100 ms-I. Find its wavelength. (2004 - 1 Mark) Find out atomic number and mass number of the element X. Also identify the element. Find the velocity (ms-') of electron in first Bohr's orbit of radius a,. Also find the de Broglie's wavelength (in m). Find the orbital angular momentum of 2p orbital of hydrogen atom in units of h I2n. (2005 - 2 Marks)



STRUCUTRE OPATOM , c.31

am Each question contains statements given in two columns, which have to be matched The statements in Column-I are labelled A, B. C and D, while the statements in Column-11 are labelledp, q, ,: s and t. Any given statement in Column-1 can have correct matching with ONE OR MORE s{atement(s) in Column-11. The appropriate bubbles corresponding to the answers to these questions have to be darkened as illustrated in the following example : Ifthe correct matches are A-p, s and t; B-q andr; C-p andq; andD-s then the correct darkening ofbubbles will look like the given.

~ q . i s t , '

B G90000 c 00000 , . D G9@080

1. According to Bohr's theoly, ' (2406- 6M) E,, = Total energy, K,8 = Kinetic energy, V,, = Potential energy, r,) = Radius of nth orbit Match the following :

Column I Column I1 (A) V,/%=? ,@) 0 ) If radius of nth orbit E,X, x = ? (4) -1 (C) Angular momentum in lowest orbital (r) -2

2. Match the entries in Column I withthe correctly related quantum number@) in Column 11. Indicate your answer by darkening the appropriate bubbles ofthe4 x 4 matrix given in the ORS (2008 - 6M)

Column I Columnll (A) Orbital angular momentum of the electron in a (p) Principal quantum number

hydrogen-like atomic orbital @) A hydrogen-like one-electron wave function ((1) Azi,muthal quantum number

obeying Pauli principle (C) Shape, size and orientation of hydrogen- like (r) Magnetic quantum number

. ~

atomic orbitals @) Probability density of electron at the iudleus (s) Electron spin quantum number

in hydrogen-like atom

The hydrogen-like species Liz+ is in a spherically symmetric state S, with one radial node. Upon absorbing light the ion undergoes transition to a state S2. The state S, has one radial node and its energy is equal to the ground state energy ofthe hydrogen atom.

(2010) 1 . The state S, is :

(a) 1 s @) 2s ( ~ 1 2 ~ .. ( 4 3s

2. Energy ofthe state S, in units of the hydrogenatom gro'und state energy is : (a) 0.75. . @) 1.50 (c) 225 (d) 4.50

3. The orbital angul&momentum quantum number ofthe state S, is : . . (a) 0 @) 1 (c) 2 (4 3

1. ASSERTION : Nuclide :?-A1 is less stable than 4; Ca (1998 - 2 Marks)

REASON : Nuclides having odd number of protons and neutrons are generally'unstable. (a) If both assertion and reason are correct, and reason is

the correct explanation of the assertion. '@) If both assertion and reason are correct, but reason is

not the correct explanation of the assertion.. (c) If assertion is correct but reason is incorrect. (d) If assertion is incorrect but reason is correct.

2. This question contains STATEMENT-1 (Assertion):and . . STATEMENT-2 (Reason) and has 4 choices (a), (b); (c) and

(d) out ofwhich ONLY ONE is correct. STATEMENT-1 : Band gap in germanium is small. because STATEMENT-2 : The energy gap ofeach germanium atomic energy level is infinitesimallysmall. (2007)



I C-32 Topic-wise Solved Papers - CHEMISTRY I (a) Statement-1 is True, Statement-2 is True; Statement-:! is a correct explanation for statement-I I@- I B

(b) Statement-l is True, Statenrent-2 is True; Statement-2 The work function (+) of some metals is listed belo,w, The is not a correct explanation for Statement-l number ofmetals which will show photoelectric effect when (c) Statement-1 is True, Statement-2 is False

(d) Statement-1 is False. Statement-2 is True. . light of 300 nm wavelength falls on the metal-is (2011) 3. STATEMENT-1 : he plot of atomic number (y-axis) versus

number of neutrons (x-axis) for stable nuclei shows a curvature towardsx-axis from the line of 45" slope as the atomic number is increased. STATEMENT-2 : Proton-proton e!ectrostatic repulsions begin to overcome attractive forces involving protons and neutrons in heavier nuclides. .. (2008) (a) Statement-1 is True,.Statement-2 is True; Statement-:!

is a correct explanation for Statement-1 .' - ~ (b) Statement-l is ~ i e , statement-2 is True; statem'enG2

is NOT a co=ect explanation for Statement-1 (c) Statement-l is True, Statement-2 is False (d) Statement-l is ~ a l s e , Statement-2 is True

Metal I Li I Na I K I Mg ] Cu 1 Ag 1 Fe 1 Pt 1 W $(eV) 1 2.4 1 2.3 1 2.2 1 3.7 1 4.8 1 4.3 1 4.7 1 6.3 14.75

2. The maximum number of electrons that can have principal 1 . quantum numbe:; n = 3, and spin quantum m, = --, 1s 2 (2011)

3. The atomic masses of 'He' and 'Ne' are 4 and 20 a.m.u., respectively. The value ofthe de Broglie wavelengthof 'He' gas at-73C is"M" times that ofthe de Broglie wavelength of 'Ne' at 727C 'M' is (JEEAdv. 2013)

I $ JEE Main/ AlEEE . 1. In a hydrogen atom, if energy of an electron in ground state 6.

is 13.6. ev, then that in the 2"* excited state is [ZOO21 (a) 1.51 eV (b) 3.4eV (c) 6.04eV (d) 13.6eV.

2. Uncertainty in position of a minute particle of mass 25 g in space is 10"~m. What is the uncertainty in its velocity (in ms-I) ? (h = 6.6 x 1 0-34 JS) 7. I . ' [2002] (a) 2.1 ~ ~ 1 0 " ~ ' ' (b) 0.5 x (c) 2.1 x (d) 0.5 x

3. The number of d-electrons retained in Fez+ (20031 (At. no.of Fe = 26) ion is (a) 4 (b) 5. 8. (cl 6 (d) 3.

4. The orbital angular momentum for anslectron revolving in

In Bohr series of lines dfhydrogen spectrum, the third line from thered end corresponds to d i c h one ofthe following inter-orbit jumps of the eleckon 'for Bohr orbits in an atom' of hydrogen . , [ZOO31 (a) 5 -+ 2 . . ( b ) 4 + l (c) 2 + 5 (d) 3 + 2 The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity o f 10 metres per second is

, >

approjtimately . . . .

(20031 (a) 10~"metres (b) 10-16metres ' , (c) 10-25.metres , (d) 10-33metres ~lanck's constant, h=.6.63 x .IS -

Which of the following sets of quantum numbers is correct for an electron in 4f orbital ? [2OO4l (a) n=4,!=3,m=+l,s=+%

I h (b) n=4,!=4,m=-4,s=-% an orbit is given by m.%. This momentum for an (c) 0=4 , t=3 ,m=+4 , s=+!h s-electron will be given by [ZOO31

(a) zero

1 h (d) +-.- 2 2n \

5. Which one of the following groupings represents a collection of isoelectronic species ?(At. nos. : Cs : 55, Br: 35) 120031 (a) N3-, F, Na+ (b) ~ e , AP+, Cl- (c) Caz", Cs', Br (d) Na+, Ca2+, MgZ+

(d) n=3 ,1=2 ,m=-Z,s=+% 9. Consider the ground state of Cr atom (X = 24). The number

of electrons with the azimuthal quantum numbers, e = 1 and 2 are, respectively [2004] (a)- 16and4 @) 12and5 (c) 12&d4 ' ' (d) 16and5

10. The wavelength oftheradiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1 . 0 9 7 ~ 107m-I) I20041 (a) 406nm (b) 192nm , ' (c) 91nm (d) 9.1x104nm



11. Which one of the following sets of ions represents the collection of isoelectronic species? [2004] (a) K+, CI; MgZ+, Sc3+ (b) NaC, CaZf, Sc3+, F- (c) KC, Ca2+, Sc3+, Cl- (d) ~ a + ; Mg2+, APf, CI- . .

, ( ~ t o m i c nos. : F = 9, CI =,I?, Na= 11, Mg = 12,A1= 13, K=19,Ca=20,Sc=21)

12. In a multi-electron atom, whicli of the .foliowing oibitals described by the three quantum members will have the sanie energy in the absence i f magnetic and electric fields? , ~

120051 (A) n= l , /=O ,m=@ (B) n=2,1=0,m=O (C) n = 2 , l = l , m = l @) n = 3 , / = 2 , m = l (E) n=3,1=2,m=O (a) (D)and (~ ) , - (b) (C)and(D) ( 4 (B) and (C) (d) (A) and (B) ,

13. Of the following sets which onedoes,NOT contain isoelectronic species? , [2005]'

(c) CN-, N2, c:- (d) PO:-, SO:-, C104 14. According to Bohr's theory, the angular momentum of an

electron in 5Ih orbit is 120061 (a) IOhln , .(b) 2 . 5 h l n (c) 25 h / n (d) 1.0 h l n

15.- uncertainty in the position of an electron (mass = 9.1 x lo5' kg) moving with a velocity 300 ms-I, accurate upto O.OOl%will be 120061 (a) 1.92~10-Zm (b) 3.84 x 10-2m~ (c) 19.2x10-Zm " (d) 5.76 x 10-Zm

(h=6.63 x 10-34Js) 16. Which one of the following sets of ions represents a

collection of isoelectronic species? [2006] . , (a) N3-, 02-, F, Sz- (b) LiC, Na+, Mg2+, Ca2+ _ (c) K+, CI-, Caz+, Sc3+ (d) Baz+, S$+, Kc, Ca2+

17. Which ofthe following sets of quantum numbers represents the highest energy of an atom? 120071 (a) n=3 ,1=0 ,m=O,s~+I /2 (b) n=3 , l= I,m=.l,s=+1/2 (c) n=3,1=2,m=l,s=+1/2 (d) n=4,l=O,m=O,s=+li2.

18. Which one of the following constitutes a group of the isoelectronic species? [2008]

(c) CN;,N~,O?,C:- ( 4 N 2 , 0 ~ , N O f , ~ 0 19. The ionization enthalpy of hydrogen atom is 1.312 x lo6 J

mol-I. The energy required to excite the electron in the atom f r o m n = l t o n = 2 i s [2008]

. ..

(a) ' 8.51 x 10SJmol-l (b) 6.56 x 1OSJmol-' (c) 7.56 x 10SJmol-' (d) 9.84 x 1OSJmoI-'

20. Calculate the wavelength (in nanometer) associated,with a proton moving at 1.0 x lo3 ms-I. (Mass of proton = 1.67 x kg and h = 6.63 x Js) (a)' OAOnm (b) 2.5 nm [2009] (c) 14.0im (d) 0.32nm . . . .

21. 1nan atom, an electron is moving with a speed of 600 mls with an accuracy of 0.005%. Certainity with which the' ',

- . position ofthe electron can belocated is ( h = 6.6 x loJ4 kg m2s:', mass ofelectron, em =9.1 x loJ1 kg) : 120091 . (a) 5.'10;10-~m (b) 1 . 9 2 ~ 1 0 - ~ m (c) 3 . 8 4 ~ 10"m (d) 1.52 x 104m

22. The energy required to break one mole bf C1 - CI bonds in C12 is 242 kJ mol-I. The longest wavelength of light capable - . of breaking a'single CI- CI bond is (c= 3 x 1 Ox ms-I and NA = 6.02 x 1.OZ3 mol-I). [2010j . . (a) 594nm (b) .640nm (c) 700nm (d) 494nm

23. Ionisation energy of Hei is 19.6 x 10-l~ J atom!'. The energy -

of the first stationary state (h = 1)of Liz+ is [ tolo] (a) 4.41 x 10-l6 Jatom-I (b) 4 . 4 1 x 10-l7 Jatom:' (c) -2.2 x 10-Is J atom-' (d) 8.82 x 10-l7 Jatom-'

24. A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the ~. emissions . is at 680 nm, the other is at: [2011] (a) l035nm (b) 325nm (c) * 743 nm (d) 518nm .- . .

25. The frequency of light emitted forthe transition n = 4 to n = 2 ofthe He' is eqtial.to the transition in H atom corresponding to which ofthe following'? [2OllRSJ , . (a) n = 2 t o n L 1 (b) n = 3 t o n = 2 (c) n = 4 t o n ? (d) n = 3 t o n = l

26. The electrons identified by quantum numbers n and e : . . . (A) n=4;!=1 (B) n = 4 , e = 0

(C) n=3,!=2 (D) n = 3 , e = 1 can be placed in order of increasing energy as : [2012] (~) . ' (c)

Structure of Atom

Documents

Transcript of Structure of Atom