Catalonia PAU Chemistry Practice Questions - Catalonia PAU Chemistry Examination - CIC Generalitat de Catalunya (Química 2n Batxillerat 2026) Exam - Catalonia PAU Chemistry Practice Questions - Catalonia PAU Chemistry Examination - CIC Generalitat de Catalunya (Química 2n Batxillerat 2026) Exam

Question 1

Which set of quantum numbers (n, l, ml, ms) represents a valid valence electron in the highest-energy populated orbital of a ground-state chlorine atom (Z = 17)?

(3, 1, 0, +1/2) (3, 2, 0, -1/2) (2, 1, -1, +1/2) (3, 0, +1, -1/2)

Correct Answer:

(3, 1, 0, +1/2)

Question 2

What is the correct ground-state electron configuration of a neutral chromium atom (Z = 24)?

[Ar] 4s² 3d⁴ [Ar] 3d⁵ 4s¹ [Ar] 4s² 3d⁵ [Ar] 3d⁶

Correct Answer:

[Ar] 3d⁵ 4s¹

Question 3

How does atomic radius vary across Period 3 of the periodic table from Sodium (Na, Z = 11) to Chlorine (Cl, Z = 17)?

Atomic radius increases because additional electrons increase electron-electron repulsion. Atomic radius remains constant because electrons are added to the same principal shell n = 3. Atomic radius decreases because increasing nuclear charge increases effective nuclear charge (Zeff), pulling valence shell electrons closer. Atomic radius decreases initially then increases sharp at Phosphorus due to subshell half-filling.

Correct Answer:

Atomic radius decreases because increasing nuclear charge increases effective nuclear charge (Zeff), pulling valence shell electrons closer.

Question 4

Why is the first ionization energy of Magnesium (Z = 12, 738 kJ/mol) higher than that of Aluminum (Z = 13, 578 kJ/mol)?

Magnesium has a larger nuclear charge than Aluminum. Aluminum's valence electron is removed from a higher-energy 3p subshell that is shielded by filled 3s orbitals. Magnesium has a smaller atomic radius than Aluminum. Aluminum forms a stable noble gas core upon losing one electron.

Correct Answer:

Aluminum's valence electron is removed from a higher-energy 3p subshell that is shielded by filled 3s orbitals.

Question 5

Why is the electron affinity of Chlorine (-349 kJ/mol) more negative (more exothermic) than that of Fluorine (-328 kJ/mol)?

Fluorine has a lower electronegativity than Chlorine. Chlorine has a smaller nuclear charge than Fluorine. Fluorine's compact 2p subshell experiences strong electron-electron repulsion, weakening the net attraction for an incoming electron. Chlorine's 3p subshell can accommodate an extra electron without requiring spin pairing.

Correct Answer:

Fluorine's compact 2p subshell experiences strong electron-electron repulsion, weakening the net attraction for an incoming electron.

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Prepare with the Catalonia PAU Chemistry Practice Questions - Catalonia PAU Chemistry Examination - CIC Generalitat de Catalunya (Química 2n Batxillerat 2026) Exam practice quiz. This question bank includes 100 questions covering reaction, equilibrium, energy, standard, and calculate. Use it to review important concepts, identify knowledge gaps, and build confidence for the related exam, course, or assessment.

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Catalonia PAU Chemistry Practice Questions - Catalonia PAU Chemistry Examination - CIC Generalitat de Catalunya (Química 2n Batxillerat 2026) Exam

This practice set contains 100 questions from the matching question bank and focuses on reaction, equilibrium, energy, standard, and calculate. Work through each question carefully, review the provided solutions, and revisit topics that need more study before your next attempt.

This is an independent study resource intended for practice and review; it is not an official examination or an endorsement by any organization named in the title.

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Catalonia PAU Chemistry Practice Questions - Catalonia PAU Chemistry Examination - CIC Generalitat de Catalunya (Química 2n Batxillerat 2026) Exam

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