Electronic Configuration, IUPAC & Blocks — MH-CET Chemistry MCQs with Solutions
Free MH-CET Chemistry Electronic Configuration, IUPAC & Blocks MCQs with step-by-step solutions (40 questions). Part of Classification of Elements and Periodicity. Practise online on Prepizo — no login needed.
▶ Practise Electronic Configuration, IUPAC & Blocks online (free)
Questions with solutions
Q1 — Electronic Configuration, IUPAC & Blocks · easy · theory
The general valence-shell configuration of the s-block elements is:
A. ns¹⁻² ✓ Correct
B. (n−1)d¹⁻¹⁰ ns⁰⁻²
C. (n−2)f¹⁻¹⁴
D. ns² np¹⁻⁶
Solution: s-block (groups 1–2) have ns¹ or ns² valence configurations.
Q2 — Electronic Configuration, IUPAC & Blocks · easy · theory
The general valence-shell configuration of the p-block elements is:
A. ns² np¹⁻⁶ ✓ Correct
B. (n−1)d¹⁻¹⁰ ns¹⁻²
C. (n−2)f¹⁻¹⁴
D. ns¹⁻²
Solution: p-block (groups 13–18): ns² np¹ to ns² np⁶.
Q3 — Electronic Configuration, IUPAC & Blocks · easy · theory
The general configuration of the d-block (transition) elements is:
A. (n−2)f¹⁻¹⁴ (n−1)d⁰⁻¹
B. ns¹⁻²
C. ns² np¹⁻⁶
D. (n−1)d¹⁻¹⁰ ns⁰⁻² ✓ Correct
Solution: Transition elements fill the (n−1)d subshell: (n−1)d¹⁻¹⁰ ns⁰⁻².
Q4 — Electronic Configuration, IUPAC & Blocks · easy · theory
The f-block (inner-transition) elements have the general configuration:
A. ns² np¹⁻⁶
B. (n−1)d¹⁻¹⁰ ns²
C. ns¹⁻²
D. (n−2)f¹⁻¹⁴ (n−1)d⁰⁻¹ ns² ✓ Correct
Solution: Inner-transition elements fill the (n−2)f subshell.
Q5 — Electronic Configuration, IUPAC & Blocks · medium · theory
Elements of groups 1, 2 and 13–17 are collectively called:
A. Representative (main-group) elements ✓ Correct
B. Inner-transition elements
C. Inert gases
D. Transition elements
Solution: s-block and p-block (except group 18) are the representative or main-group elements.
Q6 — Electronic Configuration, IUPAC & Blocks · medium · theory
The IUPAC numerical roots for digits 0, 1, 2, 3 are:
A. nil, mono, di, tri
B. nil, un, bi, tri ✓ Correct
C. non, un, bi, tri
D. zero, un, bi, ter
Solution: Roots: 0 nil, 1 un, 2 bi, 3 tri, 4 quad, 5 pent, 6 hex, 7 sept, 8 oct, 9 enn.
Q7 — Electronic Configuration, IUPAC & Blocks · easy · theory
In IUPAC nomenclature for Z > 100, the name always ends with the suffix:
A. -ium ✓ Correct
B. -ate
C. -ous
D. -ide
Solution: The digit-root name is completed with the suffix "-ium".
Q8 — Electronic Configuration, IUPAC & Blocks · easy · theory
The inert (noble) gases have the general valence configuration:
A. ns² np⁵
B. ns² np⁶ (except He: 1s²) ✓ Correct
C. (n−1)d¹⁰ ns²
D. ns¹
Solution: Group 18 elements have completely filled ns²np⁶ shells (He is 1s²).
Q9 — Electronic Configuration, IUPAC & Blocks · medium · theory
The anomalous configuration of chromium ([Ar]3d⁵4s¹ instead of 3d⁴4s²) is due to the:
A. Higher energy of 3d
B. Larger size of 4s
C. Extra stability of a half-filled d-subshell (exchange energy + symmetry) ✓ Correct
D. Pauli exclusion violation
Solution: A half-filled 3d⁵ (with 4s¹) is more stable owing to exchange energy and symmetrical distribution.
Q10 — Electronic Configuration, IUPAC & Blocks · medium · theory
Copper adopts [Ar]3d¹⁰4s¹ rather than [Ar]3d⁹4s² because of the stability of a:
A. Completely-filled d-subshell ✓ Correct
B. Vacant d-subshell
C. Half-filled p-subshell
D. Half-filled s-subshell
Solution: The fully-filled 3d¹⁰ is extra stable, so one 4s electron shifts to 3d.
Q11 — Electronic Configuration, IUPAC & Blocks · medium · theory
The block of an element is decided by the subshell:
A. With the highest energy always
B. That receives the last (differentiating) electron ✓ Correct
C. That is completely filled
D. Closest to the nucleus
Solution: The subshell into which the last electron enters (s, p, d or f) fixes the block.
Q12 — Electronic Configuration, IUPAC & Blocks · medium · theory
The zig-zag line in the p-block separates:
A. s-block from p-block
B. Representative from transition elements
C. Metals from non-metals (with metalloids along it) ✓ Correct
D. Solids from gases
Solution: The staircase line marks the metal/non-metal divide, with metalloids (B, Si, Ge, As, Sb, Te) along it.
Q13 — Electronic Configuration, IUPAC & Blocks · hard · theory
Palladium has the unusual ground-state configuration:
A. [Kr] 4d¹⁰ 5s²
B. [Kr] 4d¹⁰ 5s⁰ ✓ Correct
C. [Kr] 4d⁸ 5s²
D. [Kr] 4d⁹ 5s¹
Solution: Pd (Z = 46) is unique: [Kr]4d¹⁰ with an EMPTY 5s (5s⁰).
Q14 — Electronic Configuration, IUPAC & Blocks · easy · theory
Transition elements are also called d-block elements because their differentiating electron enters the:
A. ns subshell
B. (n−2)f subshell
C. (n−1)d subshell ✓ Correct
D. np subshell
Solution: The last electron goes into the (n−1)d orbitals.
Q15 — Electronic Configuration, IUPAC & Blocks · easy · theory
Elements with configuration ending in ns² np⁶ (group 18) are chemically:
A. Inert / very unreactive (stable octet) ✓ Correct
B. Strong oxidising acids
C. Strong reducing agents
D. Highly reactive metals
Solution: A complete octet gives noble gases their characteristic inertness.
Q16 — Electronic Configuration, IUPAC & Blocks · easy · theory
The lanthanides and actinides are placed in the ___ block:
A. p
B. s
C. f ✓ Correct
D. d
Solution: Inner-transition elements (4f and 5f filling) constitute the f-block.
Q17 — Electronic Configuration, IUPAC & Blocks · easy · numerical
The IUPAC name of the element with Z = 104 is:
A. Unniltrium (Unt)
B. Unnilpentium (Unp)
C. Unnilquadium (Unq) ✓ Correct
D. Ununquadium (Uuq)
Solution: 1-0-4 → un-nil-quad-ium = Unnilquadium, symbol Unq.
Q18 — Electronic Configuration, IUPAC & Blocks · medium · numerical
The IUPAC name of the element with Z = 120 is:
A. Ununnilium (Uun)
B. Binilunium (Bnu)
C. Unnilbium (Unb)
D. Unbinilium (Ubn) ✓ Correct
Solution: 1-2-0 → un-bi-nil-ium = Unbinilium, symbol Ubn.
Q19 — Electronic Configuration, IUPAC & Blocks · medium · numerical
The IUPAC name of the element with Z = 118 is:
A. Unniloctium (Uno)
B. Octounnium (Oun)
C. Unbioctium (Ubo)
D. Ununoctium (Uuo) ✓ Correct
Solution: 1-1-8 → un-un-oct-ium = Ununoctium, symbol Uuo.
Q20 — Electronic Configuration, IUPAC & Blocks · easy · numerical
The IUPAC name of the element with Z = 105 is:
A. Unnilpentium (Unp) ✓ Correct
B. Unnilquadium (Unq)
C. Nilunpentium (Nup)
D. Ununpentium (Uup)
Solution: 1-0-5 → un-nil-pent-ium = Unnilpentium, symbol Unp.
Q21 — Electronic Configuration, IUPAC & Blocks · medium · numerical
An element has the ground-state configuration [Ar] 3d⁵ 4s¹. It is:
A. Iron (Z = 26)
B. Manganese (Z = 25)
C. Chromium (Cr, Z = 24) ✓ Correct
D. Vanadium (Z = 23)
Solution: [Ar]3d⁵4s¹ = 24 electrons ⇒ Cr, an anomalous configuration.
Q22 — Electronic Configuration, IUPAC & Blocks · medium · numerical
An element with configuration [Ar] 3d¹⁰ 4s¹ is:
A. Nickel (Z = 28)
B. Zinc (Z = 30)
C. Potassium (Z = 19)
D. Copper (Cu, Z = 29) ✓ Correct
Solution: [Ar]3d¹⁰4s¹ = 29 electrons ⇒ Cu (anomalous).
Q23 — Electronic Configuration, IUPAC & Blocks · medium · numerical
The element with configuration [Ne] 3s² 3p⁴ belongs to:
A. Period 3, Group 14, p-block
B. Period 3, Group 16, p-block ✓ Correct
C. Period 3, Group 6, d-block
D. Period 2, Group 16, p-block
Solution: n = 3 ⇒ period 3; 6 valence electrons (3s²3p⁴) ⇒ group 16; last electron in p ⇒ p-block.
Q24 — Electronic Configuration, IUPAC & Blocks · medium · numerical
The element with configuration [Ar] 3d³ 4s² is in:
A. Period 4, Group 5, d-block ✓ Correct
B. Period 3, Group 5
C. Period 4, Group 15
D. Period 4, Group 3, d-block
Solution: Group number for d-block = (n−1)d + ns electrons = 3 + 2 = 5 ⇒ V.
Q25 — Electronic Configuration, IUPAC & Blocks · medium · numerical
An element belongs to Group 13 and Period 3. Its valence-shell configuration is:
A. 3s² 3p¹ ✓ Correct
B. 3s² 3p³
C. 2s² 2p¹
D. 3s¹
Solution: Period 3 ⇒ n = 3; group 13 ⇒ 3 valence electrons ⇒ 3s²3p¹ (Al).
Q26 — Electronic Configuration, IUPAC & Blocks · hard · numerical
The number of unpaired electrons in the ground state of Cr ([Ar]3d⁵4s¹) is:
A. 5
B. 6 ✓ Correct
C. 4
D. 1
Solution: 3d⁵ (5 unpaired) + 4s¹ (1 unpaired) = 6 unpaired electrons.
Q27 — Electronic Configuration, IUPAC & Blocks · medium · numerical
An element with atomic number 30 (Zn) has the configuration [Ar]3d¹⁰4s² and belongs to:
A. Period 3, Group 12
B. Period 4, Group 12, d-block ✓ Correct
C. Period 4, Group 10, d-block
D. Period 4, Group 2, s-block
Solution: Zn: filled 3d¹⁰ and 4s² ⇒ group 12, d-block, period 4.
Q28 — Electronic Configuration, IUPAC & Blocks · medium · numerical
The block of the element with configuration [Xe] 4f⁷ 6s² is:
A. s-block
B. p-block
C. f-block (inner-transition) ✓ Correct
D. d-block
Solution: The differentiating electron enters 4f ⇒ f-block (this is Eu).
Q29 — Electronic Configuration, IUPAC & Blocks · medium · numerical
An element in Group 17, Period 4 has the valence configuration:
A. 4s² 3d⁵
B. 3s² 3p⁵
C. 4s² 4p⁶
D. 4s² 4p⁵ ✓ Correct
Solution: Period 4, group 17 ⇒ 7 valence electrons ⇒ 4s²4p⁵ (Br).
Q30 — Electronic Configuration, IUPAC & Blocks · hard · numerical
Platinum (Z = 78) has the ground-state configuration:
A. [Xe] 4f¹⁴ 5d⁸ 6s²
B. [Xe] 4f¹⁴ 5d⁹ 6s¹ ✓ Correct
C. [Xe] 5d¹⁰ 6s²
D. [Xe] 4f¹⁴ 5d¹⁰ 6s⁰
Solution: Pt shows the anomalous [Xe]4f¹⁴5d⁹6s¹.