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

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

1.​ Which set of quantum numbers (n, l, m_l, m_s) is valid for an electron in a ground-state
arsenic atom?


A. 3, 3, 0, +½


B. 4, 2, –1, –½


C. 4, 1, 2, +½


D. 3, 2, –3, –½


Correct Answer: B


Short Explanation: l must be < n, |m_l| ≤ l, and m_s = ±½. Only B satisfies all constraints (l = 2 <
n = 4; |m_l| = 1 ≤ 2).


2.​ The first ionization energy of aluminum is 578 kJ mol⁻¹. What is the minimum frequency
of light that can ionize a single Al atom?


A. 8.69 × 10¹⁴ s⁻¹


B. 1.45 × 10¹⁵ s⁻¹

,C. 2.90 × 10¹⁵ s⁻¹


D. 5.78 × 10¹⁴ s⁻¹


Correct Answer: B


Calculation: E_per_atom = 578 000 J / 6.022 × 10²³ = 9.60 × 10⁻¹⁹ J; ν = E/h = 9.60 × 10⁻¹⁹ J /
6.626 × 10⁻³⁴ J·s = 1.45 × 10¹⁵ s⁻¹.


3.​ Arrange the following ions in order of increasing ionic radius: Mg²⁺, Na⁺, F⁻, O²⁻.


A. Mg²⁺ < Na⁺ < F⁻ < O²⁻


B. O²⁻ < F⁻ < Na⁺ < Mg²⁺


C. Na⁺ < Mg²⁺ < F⁻ < O²⁻


D. Mg²⁺ < O²⁻ < F⁻ < Na⁺


Correct Answer: A


Trend: Isoelectronic series 10 e⁻; radius increases as Z decreases: Mg²⁺ (Z=12) smallest, O²⁻
(Z=8) largest.


4.​ How many nodes (total) does a 4d orbital possess?


A. 3


B. 4

, C. 5


D. 2


Correct Answer: A


Formula: total nodes = n – 1 = 4 – 1 = 3.


5.​ Which element has the largest third ionization energy?


A. Al


B. Si


C. Mg


D. Na


Correct Answer: C


Reason: Removing the third electron from Mg breaks the stable neon core (2p⁶), whereas Al and
Si remove 3p electrons; Na has only one valence electron.


6.​ What is the electron configuration of the Co³⁺ ion?


A. [Ar] 3d⁶


B. [Ar] 3d⁷