F Block Elements Mock Tests

14 questions available

F Block Elements Mock Test 1

Questions: 14

Sample Questions

CUET Chemistry

Which of the following lanthanoid ions is diamagnetic? (Atomic numbers: Ce = 58, Pr = 59, Nd = 60, Lu = 71)

A Ce⁴⁺

B Pr³⁺

C Nd³⁺

D Sm³⁺

CUET Chemistry

Which of the following statements is correct about the lanthanoid contraction?

A It is the gradual decrease in atomic/ionic size across the lanthanoid series

B It is the increase in atomic size across the lanthanoid series

C It causes lanthanoids to have different chemical properties

D It is caused by poor shielding of 4f electrons

CUET Chemistry

Lanthanoid contraction is responsible for which of the following observations?

A Lanthanoids are highly reactive and cannot be extracted from their oxides

B The atomic radii of scandium and yttrium are nearly identical

C The first ionisation enthalpy of lanthanoids decreases across the period

D The atomic radii of Zr (40) and Hf (72) are nearly identical

CUET Chemistry

What is the most effective method for separating lanthanoids from each other?

A Crystallisation

B Solvent extraction

C Ion exchange chromatography

D Distillation

CUET Chemistry

Why is the +3 oxidation state the most characteristic and stable state for lanthanoids?

A Because they have 3 valence electrons

B Because the +3 state gives a favourable balance of ionisation energies and lattice/hydration energies

C Because they only have 3 electrons in their outermost shell

D Because +3 is the only oxidation state they can exhibit

CUET Chemistry

Which actinoid exhibits the widest range of oxidation states: actinium (Ac, Z=89), thorium (Th, Z=90), protactinium (Pa, Z=91), or uranium (U, Z=92)?

A Actinium (Ac)

B Thorium (Th)

C Protactinium (Pa)

D Uranium (U)

CUET Chemistry

The lanthanoid contraction is responsible for which of the following observations?

A Lanthanoids are highly reactive non-metals

B The atomic radii of Zr (40) and Hf (72) are nearly identical

C Lanthanoids have low ionisation enthalpies

D The basicity of lanthanoid hydroxides increases across the series

CUET Chemistry

All actinoids are radioactive. Which actinoid has the longest-lived isotope and what is its half-life?

A Uranium-238 (4.5 × 10⁹ years)

B Thorium-232 (1.4 × 10¹⁰ years)

C Plutonium-239 (2.4 × 10⁴ years)

D Neptunium-237 (2.1 × 10⁶ years)

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