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<h3 align="center">CHM142 General Chemistry: Homework 2</h3>

**Question 1 (4 points):** Given 2 H<sub>2</sub> (g) + O<sub>2</sub> (g) → 2 H<sub>2</sub>O (g) Δ H = - 484 kJ.

(a) Which element is oxidized and which is reduced in the reaction? Determine the oxidation number of each element to support your anwer.  
(b) What is the enthalpy change for the formation of hydrogen and oxygen from one mole of steam? H<sub>2</sub>O (g) → H<sub>2</sub> (g) + ½ O<sub>2</sub>  

**Question 2 (4 points):** Identify the specific element that corresponds to each of the following electron configurations and indicate the number of unpaired electrons for each: (a) 1s<sup>2</sup>2s<sup>2</sup>, (b) 1s<sup>2</sup>2s<sup>2</sup>2p<sup>4</sup>, (c) [Ar]4s<sup>1</sup>3d<sup>5</sup>, (d) [Kr]5s<sup>2</sup>4d<sup>10</sup>5p<sup>4</sup>

**Question 3 (2 points):** Write the full electron configuration of the most stable ions of the elements in Question 2.

**Discussion is encouraged, but plagiarism is prohibited. Plagiarized part(s), if detected, receive zero points.**

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