Chapter-4 The d- and f-Block Elements — Online MCQ Test
CHEMISTRY · CLASS 12 INTER II YEAR · Andhra State Board
Practice Chapter-4 The d- and f-Block Elements with a free chapter-wise online MCQ test.
This chapter covers: transition elements - lanthanides - actinides - coordination compounds.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-4 The d- and f-Block Elements — Important Questions & Answers
Which of the following elements is NOT a transition metal?
- A. Iron (Fe)
- B. Copper (Cu)
- C. Zinc (Zn)
- D. Gallium (Ga)
Answer: D. Gallium (Ga)
Gallium (Ga) is a p-block element with configuration [Ar]3d¹⁰4s²4p¹. Transition metals have partially filled d-orbitals in their ground or common oxidation states; Zn, though having filled d-orbitals, is often considered a transition metal due to its position and properties.
Gallium (Ga) is a p-block element with configuration [Ar]3d¹⁰4s²4p¹. Transition metals have partially filled d-orbitals in their ground or common oxidation states; Zn, though having filled d-orbitals, is often considered a transition metal due to its position and properties.
What is the general electronic configuration of d-block elements?
- A. (n-1)d¹⁻¹⁰ ns¹⁻²
- B. (n-1)d⁰⁻¹⁰ ns¹⁻³
- C. (n-2)d¹⁻¹⁰ ns¹⁻²
- D. (n-1)d⁵⁻¹⁵ ns¹⁻²
Answer: A. (n-1)d¹⁻¹⁰ ns¹⁻²
d-block elements have electrons filling the (n-1)d orbitals with configurations ranging from (n-1)d¹ to (n-1)d¹⁰ along with ns¹ or ns² electrons in the outermost shell.
d-block elements have electrons filling the (n-1)d orbitals with configurations ranging from (n-1)d¹ to (n-1)d¹⁰ along with ns¹ or ns² electrons in the outermost shell.
What is the oxidation state of Mn in the complex ion [MnO₄]⁻?
- A. +5
- B. +6
- C. +7
- D. +4
Answer: C. +7
In [MnO₄]⁻, oxygen has oxidation state -2. With 4 oxygen atoms: total = -8. Since the ion has charge -1, Mn must be +7 (as +7 - 8 = -1).
In [MnO₄]⁻, oxygen has oxidation state -2. With 4 oxygen atoms: total = -8. Since the ion has charge -1, Mn must be +7 (as +7 - 8 = -1).
The magnetic moment of [Co(NH₃)₆]³⁺ complex is zero. This indicates:
- A. Co is in +2 oxidation state
- B. Co is in +3 oxidation state with all d-electrons paired
- C. Ammonia is a very weak field ligand
- D. The complex is paramagnetic
Answer: B. Co is in +3 oxidation state with all d-electrons paired
In [Co(NH₃)₆]³⁺, Co³⁺ has d⁶ configuration. NH₃ is a strong field ligand causing complete pairing of all 6 electrons (t₂g⁶), resulting in zero magnetic moment.
In [Co(NH₃)₆]³⁺, Co³⁺ has d⁶ configuration. NH₃ is a strong field ligand causing complete pairing of all 6 electrons (t₂g⁶), resulting in zero magnetic moment.
IUPAC nomenclature for [Co(NH₃)₅Cl]²⁺ would be:
- A. Pentaammineaminechloridocobalt(II) ion
- B. Pentaamminechloridocobalt(III) ion
- C. Chloridopentaamminecobalt(II) ion
- D. Amminepentachloridocobalt(III) complex
Answer: B. Pentaamminechloridocobalt(III) ion
Following IUPAC rules: anions are named first (chlorido), then ligands in alphabetical order (pentaammine), then metal and oxidation state. Co³⁺ has d⁶ configuration. Charge: 5(0) + (-1) + Co = +2, so Co is +3.
Following IUPAC rules: anions are named first (chlorido), then ligands in alphabetical order (pentaammine), then metal and oxidation state. Co³⁺ has d⁶ configuration. Charge: 5(0) + (-1) + Co = +2, so Co is +3.