Daily Olympiad: Chemistry - Classification Elements [20260511] – 5 Practice Problems & Printable PDF

1. Which element belongs to the d-block but is not considered a transition metal?

A. Manganese B. Zinc C. Iron D. Chromium

Solution

Correct: B

Zinc has a completely filled d-orbital (3d¹⁰) and does not exhibit variable oxidation states or catalytic properties, making it a d-block element but not a transition metal.

2. The element with the highest third ionization enthalpy in group 13 is ____.

A. Aluminum B. Boron C. Gallium D. Indium

Solution

Correct: A

Aluminum achieves a noble gas configuration (Ne) after losing three electrons, requiring significantly higher third ionization energy compared to other group members.

3. Which of these series of isoelectronic ions shows the correct order of atomic radius?

A. Na⁺ > Mg²⁺ > Al³⁺ > O²⁻ B. O²⁻ > F⁻ > Ne > Na⁺ C. F⁻ > Na⁺ > Mg²⁺ > Al³⁺ D. Al³⁺ > Mg²⁺ > F⁻ > O²⁻

Solution

Correct: B

O²⁻ has the largest radius due to maximum electron-electron repulsion among isoelectronic species, followed by F⁻, Ne, and progressively decreasing with increasing positive charge.

4. Which element exhibits the most exothermic electron gain enthalpy among halogens?

A. Fluorine B. Chlorine C. Bromine D. Iodine

Solution

Correct: B

Chlorine has a larger atomic size than fluorine but stronger effective nuclear attraction, leading to exothermic electron gain compared to smaller fluorine atoms with strong electron-electron repulsion.

5. The lanthanide contraction directly affects the atomic radius similarity between which pair?

A. Zr and Hf B. Ti and Zr C. Y and La D. Sc and Y

Solution

Correct: A

Lanthanides reduce 6s orbital radii of subsequent elements (like Hf compared to Zr) due to poor shielding by 4f electrons, causing similar atomic radii.

Daily Olympiad: Chemistry - Classification Elements [20260511]

1. Which element belongs to the d-block but is not considered a transition metal?

2. The element with the highest third ionization enthalpy in group 13 is ____.

3. Which of these series of isoelectronic ions shows the correct order of atomic radius?

4. Which element exhibits the most exothermic electron gain enthalpy among halogens?

5. The lanthanide contraction directly affects the atomic radius similarity between which pair?

Related Practice Tests

Daily Olympiad: Chemistry - Organic Chemistry [20260512]

Daily Olympiad: Chemistry - Equilibrium [20260523]

Daily Olympiad: Chemistry - Surface Chemistry [20260511]

Discussion & Comments