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Quantum Numbers and Electron Configuration

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Quantum Numbers

  1. Which of the following set a of quantum numbers is correct for an electron in 4f orbital?

(1) n = 4, l =3, m = +4, s = +1/2 (2) n = 4, l = 4, m = 4, s = 1/2

(3) n = 4, l = 3, m = +1, s = +1/2 (4) n = 3, l=2, m = 2, s = +1/2

  1. Which one of the following sets of ions represents the collection of isoelectronic species ?

(1) K +, Cl , Mg 2+ , Sc 3+ (2) Na +, Ca 2+ , Sc 3+ , F

(3) K +, Ca 2+ , Sc 3+ , Cl (4) Na +, Mg 2+ , Al 3+ , Cl

  1. Which one of the following sets of ions represents a collection of isoelectronic species ?

(1) N 3, O 2, F , S 2 (2) Li +, Na +, Mg 2+ , Ca 2+

(3) K +, Cl , Ca 2+ , Sc 3+ (4) Ba 2+ , Sr 2+ , K +, Ca 2+

  1. The increasing order of the ionic radii of the given isoelectronic species is

(1) Ca 2+ , K +, Cl , S 2 (2) K +, S 2, Ca 2+ , Cl

(3) Cl , Ca 2+ , K +, S 2 (4) S 2, Cl , Ca 2+ , K +

  1. In an atom how many orbital(s) will have the quantum numbers; n=3, l=1, m= -1, s= -1/2

(1) 5 (2) 3 (3) 1 (4) 7

  1. Given (A) n=5, m=+1 , (B) n=2, l=1, m= -1, s= -1/2

The maximum number of electron(s) in an atom that can have the quantum numbers as given

in (A) and (B) are respectively

(1) 23 and 1 (2) 8 and 1 (3) 2 and 4 (4) 4 and 1

  1. The total number of orbitals associated with the principal quantum number 5 is:

(1) 5 (2) 20 (3) 25 (4) 10

  1. The group having isoelectronic species is :

(1) O , F , Na, Mg + (3) O , F , Na +, Mg 2+

(2) O 2, F , Na, Mg 2+ (4) O 2, F , Na +, Mg 2+

  1. Among the following, the energy of 2s orbital is lowest in:

(1) K (2) H (3) Li (4) Na

10 .The correct statement about probability density (except at infinite distance from nucleus is

(1) It can be zero for 1s orbital (2) it can be negative for 2p orbital

(3) it can be zero for 3p orbital (4) it can never be zero for 2s orbital

11 . The number of subshell associated with n=4 and m= -2 quantum numbers is

(1) 8 (2) 2 (3) 16 (4) 4

12 . The number of orbitals associated with quantum numbers n= 5 and m s = -1/2 is

(1) 11 (2) 25 (3) 50 (4) 15

13 . A certain orbital has no angular nodes and two radial nodes. The orbital is :

(1) 2s (2) 3s (3) 3p (4) 2p

14 . The orbital having two radial as well as two angular nodes is

(1) 3p (2) 4f (3) 4d (4) 5d

  1. Which of the following sets of quantum numbers is not allowed?

(A) (B)

(C) (D)

  1. Consider the following statements :

(a) The principal quantum number n is a positive integer with values of n = 1, 2, 3, .

(b) The azimuthal quantum number l for a given n (principal quantum number) can have values as

l = 0, 1, 2, . n

(c) Magnetic orbital quantum number m l for aparticular l (azimuthal quantum number) has (2 l+

  1. values.

(d) 1/2 are the two possible orientations of electron spin.

(e) For l = 5, there will be a total of 9 orbital.

Which of the above statements are correct ?

(A) (a), (b) and (c) (B) (a), (c), (d) and (e)

(C) (a), (c) and (d) (D) ( a), (b), (c) and (d) 17 . The number of radial and angular nodes in 4d orbital are. respectively

(A) 1 and 2 (B) 3 and 2 (C) 1 and 0 (D) 2 and 1

  1. Maximum number of electrons that can be accommodated in shell with n = 4 are :

(1) 16 (2) 32 (3) 72 (4) 56 .

19 . The number of radial node/s for 3p orbital is :

(a) 3 (b) 2 (c) 1 (d) 4

20 . Correct statements for an element with atomic number 9 are

A. There can be 5 electrons for which m! = + "

and 4 electrons for which m! = "

B. There is only one electron in $ orbital

C. The last electron goes to orbital with n = 2 and = 1

  1. The sum of angular nodes of all the atomic orbitals is 1 .

Choose the correct answer from the options given below:

(1) C and D Only (2) A and C Only (3) A, C and D Only (4) A and B Only

21 . Which of the following statements are true?

(A) The subsidiary quantum number describes the shape of the orbital occupied by the electron.

(B) is the boundary surface diagram of the 2 % orbital.

(C) The + and - signs in the wave function of the 2 % orbital refer to charge.

(D) The wave function of 2 % orbital is zero everywhere in the xy plane.

(1) (B) and (D) only (2) (A), (B) and (C) only

(3) (C) and (D) only (4) (A) and (B) only

  1. For electron in ' 2s& ' and ' 2p ' orbitals, the orbital angular momentum values, respectively are :

(1) 2 '

#(

and 0 (2) '

#(

and 2 '

#(

(3) 0 and 6 '

#(

(4) 0 and 2 '

#(

23 . The number of orbitals with n = 5, m1 = + 2 is ______. (Round off to the Nearest Integer).

24 . A certain orbital has n = 4 and m L = 3. The number of radial nodes in this orbital is ________

(Round off to the Nearest Integer)

  1. The number of given orbitals which have electron density along the axis is _____

p), p*, p+, d)* , d*+ , d)+ , d+! , d)!,*!

26 . The maximum number of orbitals which can be identified with n = 4 and m- = 0 is_____

  1. In an atom, total number of electrons having quantum numbers n = 4, |m-| = 1 and m! = "

is

  1. The number of electrons present in all the completely filled sub shells having

n = 4 and s = + "

is ___________.

(Where n = principal quantum number ands = spin quantum number) Electronic Configuration

  1. Which of the following ions has the maximum magnetic moment?

(1) Mn +2 (2) Fe +2 (3) Ti +2 (4) Cr +2 .

  1. The numbers of d -electrons retained in Fe 2+ (atomic number Fe = 26) ion is

(1) 3 (2) 4 (3) 5 (4) 6

  1. Which one of the following groups represent a collection of isoelectronic species ?

(1) N3- , F-, N a+ (2) Be, A l3+, C l- (3) C a+2, Cs +, Br (4) Na+, Ca+2, M g+2

  1. Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the

azimuthal quantum numbers, l = 1 and 2 are, respectively

(1) 12 and 4 (2) 12 and 5 (3) 16 and 4 (4) 16 and 5

  1. In a multi -electron atom, which of the following orbitals described by the three quantum

numbers will have the same energy in the absence of magnetic and electric field.

(i) n = 1, l = 0, m = 0 (ii) n =2, l = 0, m = 0 (iii) n = 2, l = 1, m = 1

(iv) n = 3, l = 2, m =1 (v) n = 3, l = 2, m = 0

(1) (iv) and (v) (2) (iii) and (iv) (3) (ii) and (iii) (4) (i) and (ii)

6.Which of the following statements in relation to the hydrogen atom is correct?

(1) 3s, 3p and 3d orbitals all have the same energy

(2) 3s and 3p orbitals are of lower energy than 3d orbital

(3) 3p orbital is lower in energy than 3d orbital

(4) 3s orbital is lower in energy than 3p orbital

7.The spin -only magnetic moment [in units of Bohr magneton ( b)] of Ni 2+ in aqueous

solution would be (Atomic number: Ni = 28)

(1) 2.84 (2) 4.90 (3) 0 (4) 1.73

  1. Which of the following set of quantum numbers represents the highest energy of an atom?

(1) n = 3, l = 0, m = 0, s = + (2) n = 3, l = 1, m =1, s = +

(3) n = 3, l = 2, m = 1, s = + (4) n = 4, l = 0, m = 0, s = +

  1. The electrons identified by quantum numbers n and l :

(a) n = 4, l = 1 (b) n = 4, l = 0 (c) n = 3, l = 2 (d) n = 3, l = 1

can be placed in order of increasing energy as :

(1) (c) < (d) < (b) < (a) (2) (d) < (b) < (c) < (a)

(3) (b) < (d) < (a) < (c) (4) (a) < (c) < (b) < (d)

10.The correct set of four quantum numbers for the valence electrons of rubidium atom

(Z = 37) is :

(1) 5, 0, 0, + (2) 5, 1, 0, + (3) 5,1, 1, + (4) 5, 0, 1, +

  1. If the principal quantum number n = 6, the correct sequence of filling of electrons will b e

(1) ns np (n 1)d (n 2)f (2) ns (n 1)d (n 2)f np

(3) ns (n 2)f np (n 1)d (4) ns (n 2)f (n 1)d np

12 .The quantum number of fo ur electrons are given below ?

I. n = 4, l = 2, m = -2, s = 1/2 II. n = 3, l = 2, m = 1, s = +1/2

III. n = 4, l = 1, m = 0, s = +1/2 IV. n = 3, l= 1, m = 1, s = 1/2

The correct order of increasing energies will be as :

(1) III < IV < II < I (2) IV < II < III < I (3) II < IV < I < III (4) I < III < II < IV

13 . In the Sixth period, the orbitals that are filled are:

(1) 6s,4f, 5d,6p (2) 6s,5d,5f,6p (3) 6s,5f,6d,6p (4) 6s,6p,6d,6f

14 . The 71st electron of an element X with an atomic number of 71 enters into the orbital :

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

15 . In which of the following pairs, the outer most electronic configuration will be the same?

(1) Cr + and Mn 2+ (2) Ni 2+ and Cu + (3) Fe 2+ and Co + (4) V 2+ and Cr +

  1. The spin only magnetic moments (in BM) for free Ti 3+ , V 2+ and Sc 3+ ions respectively are

(At.No. Sc : 21, Ti : 22, V : 23)

(1) 3.87, 1.73, 0 (2) 1.73, 3.87, 0 (3) 1.73, 0, 3.87 (4) 0, 3.87, 1.73

! " ! " ! " ! " ! " ! " ! " ! "

  1. The Eu 2+ ion is a strong reducing agent in spite of its ground state electronic configuration

(outermost) : [Atomic number of Eu = 63]

(1) 4 f 76s 2 (2) 4 f 6 (3) 4 f 7 (4) 4 f 6 6s 2

  1. Identify the element for which electronic configuration in +3 oxidation state is [Ar]3d 5 :

(1) Ru (2) Mn (3) Co (4) Fe

  1. Which of the following pair is not isoelectronic species?

(At. No, Sm, 62; Er, 68; Yb, 70; Lu,71; Eu,63; Tb,65; Tm,69)

(A) Sm 2+ and Er 3+ (B) Yb 2+ and Lu 3+ (C) Eu 2+ and Tb 4+ (D) Tb 2+ and Tm 4+

  1. The correct decreasing order of energy for the orbitals having, following set of quantum numbers:

(A) n=3 , l=0, m= 0 (B) n=4, l=0, m= 0 (C) n=3 , l=1, m= 0 (D) n=3 , l=2, m= 1

(A) (D) >(B)> (C) > (A) (B) (B) >( D)> (C) > (A)

(C) (C) >(B)> (D) > (A) (D) (B) >( C)> (D) > (A)

21 . Given below are two statements. One is labelled as Assertion A and the other is labelled as

Reason R.

Assertion A: Energy of 2s orbital of hydrogen atom is greater than that of 2s orbital of lithium.

Reason R: Energies of the orbitals in the same subshell decrease with increase in the atomic number.

In the light of the above statements, choose the correct answer from the options given below:

(A) Both A and R are true and R is the correct explanation of A.

(B) Both A and R are true and R is NOT the correct explanation of A.

(C) A is true but R is false

(D) A is false but R is true.

22 . Which of the following statements are correct?

(a) The electronic configuration of Cr is [Ar] 3d 5 4s 1 .

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

(c) In the ground state of an atom, the orbitals are filled in order of their increasing energies.

(d) The total number of nodes are given by (n -2)

Choose the most appropriate answer from the options given below:

(A) ( a), ( c) and ( d) only (B) ( a) and ( b) only

(C) ( a) and ( c) only (D) ( a), ( b) and ( c) only

23 . The electronic configuration of Pt (atomic number 78) is:

(A) [Xe] 4f 14 5d 96s 1 (B)[Kr] 4f 14 5d 10

(C) [Xe] 4f 14 5d 14 (D) [Xe] 4f 14 5d 86s 2

24 . The f orbitals are half and completely filled, respectively in lanthanide ions

(Given: Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]

(A) Eu 2+ and Tm 2+ (B) Sm 2+ and Tm 3+

(C) Tb 4+ and Yb 2+ (D) Dy 3+ and Yb 3+

25 . Given below are the quantum numbers for 4 electrons.

A. n = 3, = 2, m = 1, = + "

B. n = 4, = 1, m = 0, = + "

C. n = 4, = 2, m = 2, = "

D. n = 3, = 1, m = 1, = + "

The correct order of increasing energy is

(A) D < B < A < C (B) D < A < B < C

(C) B < D < A < C (D) B < D < C < A

26 . The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The

metal ion is.

(1) V 2+ (2) Ti 2+ (3) Cr 2+ (4) Mn 2+

27 . The number of s -electron present in an ion with 55 protons in its unipositive state is

(1) 10 (2) 9 (3) 12 (4) 8

  1. Arrange the following orbitals in decreasing order of energy.

(A) n = 3, 1 = 0, m = 0 (B) n = 4, 1 = 0, m = 0

(C) n = 3, 1 = 1, m = 0 (D) n = 3, 1 = 2, m = 1

The correct option for the order is :

(1) D > B > A > C (2) B > D > C > A

(3) D > B > C > A (4) A > C > B > D 29 . Which one of the following sets of ions represents a collection of isoelectronic species?

(Given : Atomic Number : F : 9, Cl : 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)

(1) (Li +, Na +, Mg 2+ , Ca 2+ ) (2) (Ba 2+ , Sr 2+ , K +, Ca 2+ )

(3) (N 3-, O 2-, F -, S 2-) (4) (K +, Cl -, Ca 2+ , Sc 3+ )

  1. Arrange the following elements in the increasing order of number of unpaired electrons in it.

(A) Sc (B) Cr (C) V (D) Ti (E) Mn

Choose the correct answer from the options given below:

(1) (C) < (E) < (B) < (A) < (D) (2) (B) < (C) < (D) < (E) < (A)

(3) (A) < (D) < (C) < (B) < (E) (4) (A) < (D) < (C) < (E) < (B)

  1. Compare the energies of following sets of quantum numbers for multielectron system.

(A) n = 4,1 = 1 (B) n = 4,1 = 2

(C) n = 3,1 = 1 (D) n = 3,1 = 2

(E) n = 4,1 = 0

Choose the correct answer from the options given below :

(1) (B) > (A) > (C) > (E) > (D) (2) (E) > (C) < (D) < (A) < (B)

(3) (E) > (C) > (A) > (D) > (B) (4) (C) < (E) < (D) < (A) < (B)

  1. Match List I with List II

List -I (Element) List -II (Electronic Configuration)

A. N I. [Ar ]3 d". 4 s#4p/

B. S II. [Ne ]3 s#3p0

C. Br III. [He ]2 s#2p1

D Kr IV. [Ar ]3 d". 4 s#4p2

Choose the correct answer from the options given below :

(1) A -IV, B -III, C -II, D -I (2) A -III, B -II, C -I, D -IV

(3) A -I, B -IV, C -III, D -II (4) A -II, B -I, C -IV, D -III

  1. The electronic configuration of Einsteinium is :

( Given atomic number of Einsteinium = 99 )

(1) [Rn ]5f"# 6 d.7 s# (2) [Rn ]5f"" 6 d.7 s#

(3) [Rn ]5f"1 6 d.7 s# (4) [Rn ]5f". 6 d.7 s#

  1. Choose the correct option having all the elements with d". electronic configuration from the

following:

(1) #3 Co , #4 Ni , #2 Fe , #0 Cr (2) #5 Cu , 1. Zn , 04 Cd , 03 Ag

(3) 02 Pd , #4 Ni , #

#2

Fe , #0 Cr (4) #4 Ni , #0 Cr , #2 Fe , #5 Cu

  1. The correct set of four quantum numbers for the valence electron of rubidium atom ( = 37 ) is:

(1) 5,0,0, + "

(2) 5,0,1, + "

(3) 5,1,0, + "

(4) 5,1,1, + "

  1. Diamagnetic Lanthanoid ions are:

(1) Nd 16 and Eu 16 (2) La 16 and Ce 06

(3) Nd 16 and Ce 06 (4) Lu 16 and Eu 16

  1. Given below are two statements:

Statement -I: The orbitals having same energy are called as degenerate orbitals.

Statement -II: In hydrogen atom, 3 p and 3d orbitals are not degenerate orbitals.

In the light of the above statements, choose the most appropriate answer from the options given

(1) Statement -I is true but Statement -II is false

(2) Both Statement -I and Statement -II are true.

(3) Both Statement -I and Statement -II are false

(4) Statement -I is false but Statement -II is true 38. Match List -I with List -II.

Choose the correct answer from the options given below:

(1) (A) -I, (B) -II, (C) -III, (D) -IV (2) (A) -III, (B) -IV, (C) -I, (D) -II

(3) (A) -IV, (B) -III, (C) -I, (D) -II (4) (A) -II, (B) -I, (C) -IV, (D) -III

  1. The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19)

are

(1) n = 4, = 2, m = 1, = + "

(2) n = 4, = 0, m = 0, = + "

(3) n = 3, = 0, m = 1, = + "

(4) n = 2, = 0, m = 0, = + "

  1. Which of the following electronic configuration would be associated with the highest magnetic

moment?

(1) [Ar ]3 d3 (2) [Ar] 3 d4 (3) [Ar] 3 d1 (4) [Ar ]3 d2

  1. The electronic configuration for Neodymium is :

[Atomic Number for Neodymium 60]

(1) [Xe ]4f 06 # (2) [Xe ]5f 07 s#

(3) [Xe ]4f 26 # (4) [Xe ]44 "5 "6 #

  1. A first row transition metal in its +2 oxidation state has a spin -only magnetic moment value of

3.86 BM. The atomic number of the metal is

(1) 25 (2) 26 (3) 22 (4) 23

  1. The extra stability of half -filled subshell is due to

(A) Symmetrical distribution of electrons

(B) Smaller coulombic repulsion energy

(C) The presence of electrons with the same spin in non -degenerate orbitals

(D) Larger exchange energy

(E) Relatively smaller shielding of electrons by one another

Identify the correct statements

(1) (B), (D) and (E) only (2) (A), (B), (D) and (E) only

(3) (B), (C) and (D) only (4) (A), (B) and (D) only

44 . The correct decreasing order of spin only magnetic moment values (BM ) of Cu 6, Cu #6Cr #6 and

Cr 16 ions is :

(1) Cu 6 > Cu #6 > Cr 16 > Cr #6 (2) Cu #6 > Cu 6 > Cr #6 > Cr 16

(3) Cr #6 > Cr 16 > Cu #6 > Cu 6 (4) Cr 16 > Cr #6 > Cu 6 > Cu #6

45 . The metal ions that have the calculated spin only magnetic moment value of 4.9 B.M. are

A. Cr #6 B. Fe #6 C. Fe 16 D. Co #6 E. Mn 16

Choose the correct answer from the options given below

(1) A, C and E only (2) A, D and E only (3) B and E only (4) A, B and E only

46 . Pair of transition metal ions having the same number of unpaired electrons is :

(1) V#6, Co #6 (2) Ti #6, Co #6 (3) Fe 16, Cr #6 (4) Ti 16, Mn #6

47 . Consider the ground state of chromium atom ( Z = 24 ). How many electrons are with Azimuthal

quantum number = 1 and = 2 respectively?

(1) 12 and 4 (2) 16 and 4 (3) 12 and 5 (4) 16 and 5

48 . Lanthanoid ions with 4 3 configuration are :

(A) Eu #6 (B) Gd 16 (C) Eu 16 (D) Tb 16 (E) Sm #6

List -I Species List -II Electronic distribution

(A) Cr 6# (I) 3 d4

(B) Mn 6 (II) 3 d14 s"

(C) Ni 6# (III) 3 d0

(D) V6 (IV) 3 d/4 s"Choose the correct answer from the options given below :

(1) (A) and (B) only (2) (A) and (D) only (3) (B) and (E) only (4) (B) and (C) only

Ans. (1)

  1. Which of the following linear combination of atomic orbitals will lead to formation of molecular

orbitals in homonuclear diatomic molecules [internuclear axis in z -direction] ?

A. 2 $ and 2 % B. 2 and 2 % C. 3 %7 and 3 %!,7! D. 2 and 2 $ E. 2 $ and 3 %!,7!

(1) E Only (2) A and B Only (3) D Only (4) C and D Only

Ans. (3)

  1. For hydrogen atom, the orbital/s with lowest energy is/are :

(A) 4 s (B) 3 % (C) 3 %!,7! (D) 3 $! (E) 4 $

Choose the correct answer from the options given below :

(1) (A) and (E) only (2) (B) only

(3) (A) only (4) (B), (C) and (D) only

Ans. (4)

51 . Match List -I with List -II.

List I (Transition metal ion) List II (Spin only magnetic moment (B.M.)

(A) Ti 16 (I) 3.87

(B) V#6 (II) 0.00

(C) Ni #6 (III) 1.73

(D) Sc 16 (IV) 2.84

Choose the correct answer from the options given below :

(1) (A) -(III), (B) -(I), (C) -(II), (D) -(IV) (2) (A) -(III), (B) -(I), (C) -(IV), (D) -(II)

(3) (A) -(IV), (B) -(II), (C) -(III), (D) -(I) (4) (A) -(II), (B) -(IV), (C) -(I), (D) -(III)

52 . In a multielectron atom, which of the following orbitals described by three quantum numbers with

have same energy in absence of electric and magnetic fields?

A. n = 1, = 0, m = 0 B. n = 2, = 0, m = 0 C. n = 2, = 1, m = 1

D. n = 3, = 2, m = 1 E. = 3, = 2, = 0

Choose the correct answer from the options given below :

(1) A and B only (2) B and C only (3) C and D only (4) D and E only

  1. The Azimuthal quantum number for the valence electrons of Ga + ion is _______.

(Atomic number of Ga = 31)

  1. Number of electrons that Vanadium (Z = 23) has in p -orbitals is equal to ______

  2. Ge (Z = 32) in its ground state electronic configuration has x completely filled orbitals with ml = 0.

The value of x is _______

  1. The value of magnetic quantum number of the outermost electron of Zn + ion is _________

  2. How many of the following metal ions have similar value of spin only magnetic moment in

gaseous state ? (Given : Atomic number : V,23; Cr, 24; Fe, 26; Ni,28)

V3+ ,Cr 3+ ,Fe 2+ , Ni 3+

  1. Total number of ions from the following with noble gas configuration is _________.

Sr #6(Z = 38 ), Cs 6(Z = 55 ), La #6(Z = 57 )Pb #6 (Z = 82 ), Yb #6(Z = 70 ) and Fe #6(Z = 26 )