Atomic Structure (26!08!12)

8/10/2019 Atomic Structure (26!08!12)

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ANDHERI / BORIVALI / DADAR / CHEMBUR / THANE / MULUND/ NERUL / POWAI

IIT JEE - 2014 TW TEST MARKS: 65

TIME: 1 HR TOPICS:ATOMIC STRUCTURE DATE: 26/08/12

SECTION-I

This section contains10multiple choice questions. Each question has 4 choices (A), (B ), (C ) and(D ) for its answ er, out w hich ONLY ONE is correct. (+ 3, - 1)

1. Which of the following sets of quantum number is allowable:

(a) n 2, 1, m = 0,s = +1 2 l = (b) n 2, 2,m 1,s 1 2 l

(c) n 2, 2, m 1,s 1 2 l (d) n 2, 1,m 0,s 0 l

2. Which shape is associated with the orbital designated by n 2; 1 l ?

(a) Spherical (b) Tetrahedral (c) Dumb-bell (d) Pyramidal

3. Which out of the following configurations is incorrect?

(a) 2 2 2 2 0x y z

1s 2s 2p 2p 2p (b) 2 2 1 1x y

1s 2s 2p 2p (c) 2 2 1 1 1x y z

1s 2s 2p 2p 2p (d)2 2 6 2 6 5 11s 2s 2p 3s 3p 3d 4s

4. For which of the following electron distributions in ground state, the Paulis exclusion principle is

violated?

5. In the Schrodingers wave equation represents

(a) Orbit (b) Wave function (c) Wave (d) Radial probability

6. Ground state electronic configuration of nitrogen atom can be represented by(a)

(b)

(c)

(d)

7. The ionisation potential of hydrogen atom is 13.6 eV. The energy required to remove an electron in

the n 2 state of the hydrogen atom is

(a) 3.4eV (b) 6.8eV (c) 13.6eV (d) 27.2eV


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8. The orbital diagram in which the Aufbau principle is violated is

9. The total spin and magnetic moment for the atom with atomic number 24 are:

(a) 3, 48 BM (b) 3, 35 BM (c)3

, 48 BM2

(d)3

, 35 BM2

10. The important principles that do not help in assigning electronic configuration to atoms are

(a) Aufbau rule (b) Hunds rule(c) Heisenberg uncertainty principle (d) Paulis exclusion principle

SECTION-II

This section contains7 multiple choice questions.Each question has 4 choices (A ), (B), (C ) and(D ) for its answ er, out w hich ONE OR MORE is/are correct. (+ 3, 0)

11. The isotone(s) of 7632 Ge is/are

(a) 7732 Ge (b)77

33 As (c)77

34 As (d)78

34Se

12. The atomic nucleus contains

(a) Protons (b) Neutrons (c) Electrons (d) Photons

13. Which of the following sets of quantum number is/are not permitted?

(a)1

n 3, 3,m = +1,s = +2

l = (b)1

n 3, ,m = +2,s = -2

l = 2

(c)1

n 3, 1, m = +2,s = -2

l = (d)1

n 3, 0, m = 0,s = +2

l =

14. The energy of an electron in the first energy level of H atom is 13.6eV . The possible energy value

(s) of the excited state (s) for the electron in He

is (are).

(a) 54.4eV (b) 13.6eV (c) 3.4eV (d) 6.4eV

15. A hydrogen-like species in ground state absorbs n photons having the same energy and its emitsexactly n photons when electrons transition take placed. Then, the energy of the absorbed photon

may be

(a) 91.8eV (b) 40.8eV (c) 48.4eV (d) 54.4eV

16. An electron has spin quantum number (s) 1 2 and magnetic quantum number is 1 . It can be

present in

(a) s orbital (b) d orbital (c) p orbital (d) f orbital


3/5Head Office: Andheri: 26245223 MUMBAI / DELHI/ AKOLA / KOLKATA / LUCKNOW

17. Which is correct statement in case of Hunds rule?

(a) It states that if more than one atomic orbital of the same energy is available, electrons will occupy

different atomic orbitals with parallel spins, as far as possible, in the configuration of lowest energy

(b) Total energy of many electron atom with more than one electron occupying a set of degenerated

orbitals is lowest, is far as possible, electrons occupy different atomic orbitals and have parallel

spins.

(c) Hunds rule forbid any configuration that does not violate the Paulis exclusion principle

(d) Hunds rule simple tells us which of the possible configurations is lowest in energy and other

configurations are those of excited states, higher in energy than the ground state.

SECTION-II I (Paragraph Type)This section contains2 groups of questions. Each question has 4 choices (A ), (B ), (C ) and (D ) for its

answ er, out of w hich ONLY ONE is correct. (+ 3, -1)

The characteristic X-ray wavelength for the lines of K series in elements X and Y areo

9.87A and

o

14.6A , respectively. IfMoseleys equation, 74.9 10 Z 0.75 is followed:

frequency z atomic no, c = speed of light = 83 10 m /s

18. The atomic number of X is

(a) 8 (b) 10 (c) 12 (d) 16

19. The atomic number of Y is

(a) 10 (b) 6 (c) 8 (d) 12

SECTION-IV (Integer Answer Type)This section contains 2questions. The answ er to each of the questions is a single digit integer,ranging from 0 to 9. The correct digit below the question num ber in the O R S is be bubbled. (+ 4, 0)

20. The sum of all the quantum numbers of helium atom is.

21. The magnitude of an orbital angular momentum vector of an electron ish

62

. Into how many

components will the vector split if an external field is applied to it?



ANDHERI / BORIVALI / DADAR / CHEMBUR / THANE / MULUND/ NERUL / POWAI

TOPICS:Atomic Structure (Answer Key) DATE: 26/08/12

1. a 2. c 3. a 4. c 5. b 6. a 7. a

8. b 9. a 10. c 11. b,d 12. a,b 13. a,c 14. b,c

15. a,b 16. b,c,d 17. a,b,c,d 18. c 19. a 20. 1 21. 5

Atomic Structure Solution

2. (c)

1l = , therefore p orbitals

3. (a)2 2 1 1 1

x y z1s , 2s , 2p 2p 2p (Paulis exclusion principle)

5. (b)

wave function

9. (a)

Atomic number 24

Configuration is [Ar] 5 13d , 4s , n = 6

Total spin

1

6 32

Magnetic moment n n 2 6 6 2

48 BM

11. (b, d)

Species having the same number of neutrons are called isotones.

76

32 Ge 77

33 As 78

34Se

Neutrons 34 34 34

12. (a, b)

The atomic nucleus contains protons and neutrons.

14. (b, c)

213.6 4

E Hen

n 2, 3, 4... for excited state

15. (a, b)



Exp: Number of dark lines (in absorption), i.e.,

excitation Number of bright lines (in emission), i.e., de-excitation

It is possible only when the e is excited to n 2 from ground state.

Clearly, E 91.8eV and 40.8eV are possible:

2Li He

19. (a)

7 7v

v 4.9 10 Z 0.75 Z 0.754.9 10

[You will get to know about this]

For8o

18

10

c 3 109.87 A v 0.3 10

9.87 10

18

7

0.3 10Zx 0.75 12

4.9 10

For8o

18

10

3 1014.6A v 0.2 10

14.6 10

8

y 7

0.2 10Z 0.75 10

4.9 10

20. 12He 1s ;n 1; ;m = 0;s =1 2, 1 2 l = 0

1 1Sum 1 1

2 2

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Atomic Structure (26!08!12)