ANDHERI / BORIVALI / DADAR / CHEMBUR / THANE / MULUND/ NERUL / POWAI
IIT – JEE - 2014 TIME: 1 HR
TW TEST TOPICS:ATOMIC STRUCTURE
MARKS: 65 DATE: 26/08/12
SECTION-I questi ons. ons. E ach q u estio n h as 4 cho T h is secti ectio n con co n tain s 10 multi ple choice questi ch o ices (A ), (B ), (C ) an d (+ 3, - 1) (D ) fo r its an sw er, er, o ut w h ich ONLY ONE is corr co rrect.
1.
Which of the following sets of quantum number is allowable: (a) n 2, l = 1, m = 0, 0, s = +1 +1 2 (b) n 2, l 2, m 1, s 1 2 (c) n 2, l 2, m 1, s 1 2
(d) n 2, l 1, m 0, s 0
2.
Which shape is associated with the orbital designated by n 2; l 1 ? (a) Spherical (b) Tetrahedral (c) Dumb-bell (d) Pyramidal Pyramidal
3.
Which out of the following configurations is incorrect? 2 2 6 2 6 5 1 (a) 1s 2 2s 2 2p 2x 2p2y 2 p z0 (b) 1s 2 2s 2 2p1x 2p1y (c) 1s 2 2s 2 2p1x 2p1y 2 p1z (d) 1s 2s 2p 3s 3p 3d 4s
4.
For which of the following electron distributions in ground state, the Pauli’s exclusion principle is violated?
5.
In the Schrodinger’s wave equation represents (a) Orbit (b) Wave function (c) Wave
6.
(d) Radial probability
Ground state electronic configuration of nitrogen atom can be represented by (a) (b) ( c) (d)
7.
The ionisation potential of hydrogen 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
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: 3 3 (a) 3, 48 BM (b) 3, 35 BM (c) , 48 BM (d) , 35 BM 2 2
10.
The important principles that do not help in assigning electronic configuration to atoms are (a) Aufbau rule (b) Hund’s rule (c) Heisenberg uncertainty principle (d) Pauli’s exclusion principle
SECTION-II T his section contains 7 multiple choice questions. E ach question has 4 choices (A ), (B ), (C ) an d (D ) for its an sw er, out w hich ONE OR MORE is/are co rrect. (+ 3, 0)
11.
The isotone(s) of (a)
12.
77 32
Ge
76 32
Ge is/are (b)
77 33
As
The atomic nucleus contains (a) Protons (b) Neutrons
(c)
77 34
As
(c) Electrons
(d)
78 34
Se
(d) Photons
13.
Which of the following sets of quantum number is/are not permitted? 1 1 (a) n 3, l = 3, m = +1,s = + (b) n 3, l = 2, m = +2,s = 2 2 1 1 (c) n 3, l = 1, m = +2,s = - (d) n 3, l = 0, m = 0,s = + 2 2
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 emits exactly 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
17.
Which is correct statement in case of Hund’s rule? (a) It states that if more than one atomic o rbital 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 o f degenerated orbitals is lowest, is far as possible, electrons occupy different atomic orbitals and have parallel spins. (c) Hund’s rule forbid any configuration that do es not violate the Pauli’s exclusion principle (d) Hund’s rule simple tells u s 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)
T his section contains 2 groups of questions. E ach question has 4 choices (A ), (B ), (C ) an d (D ) for its an sw er, out of w hich ONLY ONE is correct. (+ 3, -1) o
The characteristic X-ray wavelength for the lines of K series in elements X and Y are 9.87A and o
14.6A , respectively. IfMoseley’s equation, frequency z atomic no,
18.
19.
4.9 107 Z 0.75 is followed:
c = speed of light = 3 108 m / s
The atomic number of X is (a) 8 (b) 10
(c) 12
(d) 16
The atomic number of Y is (a) 10 (b) 6
(c) 8
(d) 12
SECTION-IV
(I nteger Answer Type)
T his section contains 2 questions. T he answ er to each of the q uestions is a single digit integer, ran ging from 0 to 9. The correct digit below the question num ber in the O R S is be b ubbled. (+ 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 is
6
h 2
. Into how many
components will the vector split if an external field is applied to it?
Head Office: Andheri: 26245223
MUMBAI / DELHI/ AKOLA / KOLKATA / LUCKNOW
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) l = 1,
3.
therefore p orbitals
(a)
1s2 , 2s 2 , 2p1x 2p1y 2p1z (Pauli’s exclusion principle) 5.
(b) wave function
9.
(a) Atomic number 24 Configuration is [Ar] 3d 5 , 4s1 , n = 6
1 Total spin 6 3 2 Magnetic moment n n 2 6 6 2
11.
48 BM
(b, d) Species having the same number of neutrons are called isotones. 76 32
Neutrons
Ge
34
77 33
As
34
12.
(a, b) The atomic nucleus contains protons and neutrons.
14.
(b, c)
E He
78 34
Se
34
13.6 4
n2 n 2, 3, 4... for excited state 15.
(a, b)
Head Office: Andheri: 26245223
MUMBAI / DELHI/ AKOLA / KOLKATA / LUCKNOW
Exp: Number of dark lines (in abso rption), 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:
Li He 2
19.
(a) v
v 4.9 10 7 Z 0.75 Z
4.9 10 7 [You will get to know about this] o
For 9.87 A v
0.3 1018
Zx
4.9 10
7
o
Zy
20.
4.9 10 7
3 108 9.87 10
10
0.3 1018
0.75 12
For 14.6 A v 0.2 108
c
0.75
3 108 14.6 10
10
0.2 1018
0.75 10
1
He 1s2 ; n 1; l = 0; m = 0;s = 1 2, 1 2 Sum 1
1 2
1 2
1
Head Office: Andheri: 26245223
MUMBAI / DELHI/ AKOLA / KOLKATA / LUCKNOW