Ionization energy generally increases across a period because: MCQ with Answer and Explanation

Ionization energy generally increases across a period because:
A. Atomic radius increases
B. Nuclear charge decreases
C. Effective nuclear charge increases
D. Number of shells increases
Answer: Option C
Solution (By JKExamLibrary)
Across a period, electrons are added to the same shell, but the number of protons increases, leading to a greater effective nuclear charge. This pulls electrons closer, decreasing atomic radius and making it harder to remove an electron, so ionization energy increases.

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Practice More chemistry Questions

Question #1
Which of the following hydrocarbons is an unsaturated compound?
A. C₂H₄
B. C₃H₈
C. C₅H₁₂
D. C₄H₁₀

Correct Answer: Option A


Explanation:
C₂H₄ (ethene) is an alkene with a carbon-carbon double bond, thus unsaturated. The general formula CnH₂n indicates an alkene or cycloalkane. C₃H₈, C₄H₁₀, C₅H₁₂ follow CnH₂n+2 and are saturated alkanes. Unsaturated compounds undergo addition reactions, whereas saturated undergo substitution.

This question belongs to: Science chemistry
Question #2
Which of the following metals can displace copper from copper sulfate solution?
A. Hg
B. Zn
C. Ag
D. Au

Correct Answer: Option B


Explanation:
According to the reactivity series, zinc is more reactive than copper, so Zn displaces Cu: Zn + CuSO₄ → ZnSO₄ + Cu. Silver, gold, and mercury are less reactive than copper and cannot displace it. Reactivity: K > Na > Ca > Mg > Al > Zn > Fe > Pb > Cu > Ag > Au. Displacement reactions are used in metallurgy and galvanic cells. The blue color of CuSO₄ fades as copper is deposited.

This question belongs to: Science chemistry
Question #3
Which of the following was proposed by Rutherford's alpha-particle scattering experiment?
A. Most of the mass and positive charge is concentrated in a tiny nucleus.
B. The atom is a positively charged sphere with embedded electrons.
C. Electrons exhibit wave-particle duality.
D. Electrons revolve in fixed energy orbits.

Correct Answer: Option A


Explanation:
Rutherford's experiment led to the nuclear model of the atom, concluding that almost all the mass and positive charge are concentrated in a very small central nucleus, while electrons orbit around it. Option B is Thomson's model, A is Bohr's model, and D is de Broglie's concept.

This question belongs to: Science chemistry