Free NEET Chemistry multiple-choice questions on Electronic Configuration. Attempt each question and reveal the answer with a full explanation.
Which of the following electronic configurations of an atom has the lowest ionization enthalpy? 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 5 1s 2 2s 2 2p 6 1s 2 2s 2 2p 3 The electronic configuration of an element is 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s 1 . This represents its: Ground state Excited state Anionic state Cationic state The magnetic moment of Mn 2+ ion ( Z=25 ) is: 5.92 BM 4.90 BM 3.87 BM 6.92 BM The number of electrons with l=2 in the ground state of a Nickel atom ( Z=28 ) is: 8 10 6 2 The total number of electrons that can be accommodated in all the orbitals having principal quantum number 2 and azimuthal quantum number 1 is: 6 2 8 10 The number of protons, neutrons and electrons in 175 71 Lu , respectively, are: 71, 104 and 71 104, 71 and 71 71, 71 and 104 175, 104 and 71 Maximum number of electrons in a subshell with l=3 and n=4 is: 14 10 16 12 The number of unpaired electrons in the Ni 2+ ion ( Z=28 ) is: 2 4 0 3 Which of the following is violates Hund's rule? Two electrons with parallel spins in different orbitals of the same subshell before pairing. Pairing of electrons in p -orbital after each orbital has one electron. Two electrons with opposite spins in the same orbital. Two electrons with same spin in the same orbital. Which of the following molecules/ions is NOT isoelectronic with CO ? O 2 + N 2 CN - NO + Which of the following ions has the highest number of unpaired electrons? Fe 3+ Cr 3+ Cu 2+ Zn 2+ An element has the electronic configuration [Ar] 3d 10 4s 2 4p 3 . To which group of the periodic table does it belong? 15 13 17 3 What is the maximum number of electrons that can be accommodated in the n=4 shell? 32 16 18 8 Be 2+ is isoelectronic with which of the following ions ? H + Li + Na + Mg 2+ Which one is a wrong statement? An orbital is designated by three quantum numbers while an electron in an atom is designated by four quantum numbers Total orbital angular momentum of electron in 's' orbital is equal to zero The value of m for d z 2 is zero From the following pairs of ions which one is not an iso-electronic pair? Na+ , Mg 2+ Mn 2+ , Fe 3+ Fe 2+ , Mn 2+ O 2- , F - Which pair of ions have the same electronic configuration? Fe 3+ , Mn 2+ Fe 3+ , Co 3+ Cr 3+ , Fe 3+ Sc 3+ , Cr 3+ The spin-only magnetic moment of Ti 3+ ( Z=22 ) is: 1.73 BM 2.83 BM 3.87 BM 0 BM Which of the following represents the correct electronic configuration of the Cr 3+ ion ( Z=24 )? [Ar] 3d 3 [Ar] 3d 4 4s 2 [Ar] 3d 5 4s 1 [Ar] 3d 2 4s 1 Which of the following pairs is isoelectronic? CO and NO + CO and N 2 + F - and O - O 2- and Cl - The magnetic moment of Fe 2+ ion ( Z=26 ) in Bohr Magnetons (BM) is approximately: 4.90 5.92 3.87 2.84 Which of the following ions has the electronic configuration [Ar] 3d 6 ? Co 3+ Fe 3+ Mn 2+ Ni 2+ A p-orbital can accommodate up to: 6 electrons with opposite spins in 3 orbitals 2 electrons with parallel spins 4 electrons 2 electrons with opposite spins Which of the following electronic configurations represents an excited state of a nitrogen atom? 1s 2 2s 2 2p 2 3s 1 1s 2 2s 2 2p 3 1s 2 2s 1 2p 4 1s 2 2s 2 2p 2 The total number of electrons in a nitrogen atom having spin quantum number m s = + 1 2 is: 5 2 3 4 Which of the following is the correct order of the size of the given isoelectronic species? N 3- > O 2- > F - > Na + Na + > F - > O 2- > N 3- N 3- > F - > O 2- > Na + O 2- > N 3- > F - > Na + Which of the following contains the same number of d -electrons as present in Fe 2+ (At. No. 26)? Fe atom in d subshell Cu + ion ( Z=29 ) Ni 2+ ion ( Z=28 ) Sc atom ( Z=21 ) The maximum number of electrons that can have the principal quantum number n=3 and spin quantum number m s = +1/2 is: 9 18 6 3 In the ground state of a cobalt atom ( Z=27 ), the total number of electrons with l=1 is: 12 6 18 7 The stability of half-filled and completely filled subshells is primarily due to: Relatively small shielding and higher exchange energy Low nuclear charge High screening effect Large atomic radius Which of the following is the correct order of energy for the orbitals in a multi-electron atom? 4d < 5p < 6s 5p < 4d < 6s 6s < 5p < 4d 4d < 6s < 5p The number of electrons in Fe 2+ ( Z=26 ) that have n+l=3 is: 8 6 14 10 A d -block element X has a ground state electronic configuration ending in 3d 5 4s 1 . Which of the following is true for this element? It has 6 unpaired electrons. It belongs to the 5 th group of the periodic table. It is an inert gas. The total number of s electrons is 7. What is the maximum number of electrons that can be described by the quantum numbers n=3, l=2 ? 10 2 6 14 The exchange energy is maximum for which of the following electronic configurations? 3d 5 3d 4 3d 3 3d 6 Which of the following electronic configurations represents an element with the maximum number of unpaired electrons in its ground state? [Ar] 3d 5 4s 1 [Ar] 3d 10 4s 1 [Ar] 3d 6 4s 2 [Ar] 3d 3 4s 2 The ground state electronic configuration of Silver ( Z=47 ) is: [Kr] 4d 10 5s 1 [Kr] 4d 9 5s 2 [Kr] 4d 8 5s 2 5p 1 [Xe] 4d 10 5s 1 The spin-only magnetic moment of V 3+ ion ( Z=23 ) is approximately: 2.83 BM 1.73 BM 3.87 BM 4.90 BM The number of electrons in Iron ( Z=26 ) having the azimuthal quantum number l=2 is: 6 10 2 14 The ground state electronic configuration of Molybdenum ( Z=42 ) is: [Kr] 4d 5 5s 1 [Kr] 4d 4 5s 2 [Kr] 4d 6 5s 0 [Kr] 5s 2 5p 4 The value of the magnetic moment for the Cu 2+ ion ( Z=29 ) is: 1.73 BM 2.84 BM 3.87 BM 0 BM The spin-only magnetic moment of Co 2+ ( Z=27 ) is approximately: 3.87 BM 4.90 BM 1.73 BM 2.83 BM The ground state electronic configuration of the Cu + ion ( Z=29 ) is: [Ar] 3d 10 [Ar] 3d 9 4s 1 [Ar] 3d 8 4s 2 [Ar] 3d 10 4s 1 The electronic configuration of gadolinium (Atomic number 64) is: [Xe] 4f 7 5d 1 6s 2 [Xe] 4f 3 5d 5 6s 2 [Xe] 4f 8 5d 0 6s 2 [Xe] 4f 6 5d 2 6s 2 Which of the following principles states that no two electrons in an atom can have the same set of all four quantum numbers? Pauli Exclusion Principle Hund's Rule of Maximum Multiplicity Aufbau Principle Heisenberg Uncertainty Principle The number of unpaired electrons in the ground state of Gd ( Z=64 ) is: 8 7 6 9 The orbital diagram in which both the Pauli Exclusion Principle and Hund's Rule are violated is: Two electrons with the same spin in the first box of a 2p subshell, and two electrons in the second box. Two electrons with opposite spins in a 2s orbital. Three electrons with parallel spins in three separate 2p orbitals. Two electrons with parallel spins in the first two 2p orbitals. The ratio of the magnetic moment of Fe 3+ to Fe 2+ is approximately: 1.21 1.50 0.80 1.73 Which of the following is the correct ground state electronic configuration of Palladium ( Z=46 )? [Kr] 4d 10 5s 0 [Kr] 4d 8 5s 2 [Kr] 4d 9 5s 1 [Ar] 3d 10 4s 2 4p 6 4d 10 5s 0 In the ground state electronic configuration of Copper ( Z=29 ), the number of electrons with magnetic quantum number m = 0 is: 11 10 12 13 The electronic configuration of Lanthanum ( Z=57 ) is: [Xe] 5d 1 6s 2 [Xe] 4f 1 6s 2 [Xe] 4f 1 5d 1 6s 2 [Xe] 6s 2 6p 1 Species that have the same value of (N-Z) (where N is the number of neutrons and Z is the atomic number) are called isodiaphers. Which of the following is a pair of isodiaphers? 9 19 F and 11 23 Na 6 14 C and 7 14 N 18 40 Ar and 20 40 Ca 1 3 H and 2 4 He The number of d -electrons in Fe 2+ ( Z=26 ) is not equal to the number of electrons in which of the following? p -electrons in Cl ( Z=17 ) s -electrons in Mg ( Z=12 ) p -electrons in Ne ( Z=10 ) d -electrons in Fe ( Z=26 ) Which of the following sets of quantum numbers is correct for the 19 th electron of Chromium ( Z=24 )? n=4, l=0, m l=0, m s=+1/2 n=3, l=2, m l=0, m s=+1/2 n=3, l=1, m l=1, m s=+1/2 n=4, l=1, m l=0, m s=+1/2 The electronic configuration of Europium ( Z=63 ) is: [Xe] 4f 7 6s 2 [Xe] 4f 6 5d 1 6s 2 [Xe] 4f 8 6s 1 [Xe] 4f 7 5d 1 6s 1 The correct order of the screening effect of s, p, d, f subshells of a shell of an atom on its valence electrons is: s > p > d > f f > d > p > s p > s > d > f d > f > s > p Which of the following sets of species is isoelectronic? N 3- , O 2- , Ne F -, Na, Mg 2+ Al 3+ , K +, Cl - N, O -, F 2- Which of the following is the correct order of increasing energy of listed orbitals in the atom of titanium ( Z=22 )? 3s, 3p, 4s, 3d 4s, 3s, 3p, 3d 3s, 3p, 3d, 4s 3s, 4s, 3p, 3d The exchange energy is a contributing factor to the stability of which of the following? Cr and Cu Na and Mg Fe and Co Ca and Sc