CHEM 210 Module 2 Exam (Portage Learning 2025/2026) — 30 High-Level Practice Questions with 100% Correct Answers

CHEM 210 Module 2 Exam (Portage Learning
2025/2026) — 30 High-Level Practice Questions
with 100% Correct Answers

1.​ Which quantum-number set (n, l, m , mₛ) is permissible for an electron in a

ground-state potassium atom?


A. 4, 3, −2, +½


B. 3, 2, −3, −½


C. 4, 0, 0, +½


D. 3, 1, +2, −½


Correct Answer: C


Short Explanation: l must be ≤ n − 1 and |m | ≤ l. Only set C (4, 0, 0, +½) satisfies these
rules for an s orbital in the n = 4 shell.


2.​ The first ionization energy of sodium is 496 kJ mol⁻¹. How much energy (kJ) is

required to ionize a single Na atom?


A. 8.24 × 10⁻¹⁹

,B. 4.96 × 10²


C. 1.24 × 10³


D. 2.06 × 10⁻²²


Correct Answer: A


Short Explanation: 496 kJ mol⁻¹ ÷ 6.022 × 10²³ atoms mol⁻¹ = 8.24 × 10⁻¹⁹ kJ atom⁻¹.


3.​ Which element has the largest atomic radius in its period?



A. Ar


B. Cl


C. S


D. Na


Correct Answer: D


Short Explanation: Atomic radius decreases left-to-right across a period; Na is farthest
left.


4.​ How many nodes (total) are present in a 4f orbital?

, A. 2


B. 3


C. 4


D. 5


Correct Answer: C


Short Explanation: Total nodes = n − 1 = 4 − 1 = 3 (2 spherical, 1 planar).


5.​ The electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰

6p⁶ 7s¹ corresponds to which element?


A. Fr


B. Cs


C. Ra


D. Rb


Correct Answer: B


Short Explanation: 55 electrons → Cs (cesium).