This question-specific review guide is tied to the answer reasoning for a PracticeTestVault item. Use it after you answer the question so the review stays focused on what the prompt actually tested.
What this question is testing
Objective: Apply oxidation number assignment
Prompt focus: What is the oxidation number of sulfur in the sulfate ion, SO4 with a 2 minus charge?
Why the correct answer works
Plus 6
With four oxygens at minus 2 totaling minus 8 and an ion charge of minus 2, sulfur must be plus 6.
Why the tempting wrong answer fails
The tempting wrong answer usually loses because it skips the key condition, priority, or evidence in the prompt.
Plain-language takeaway
Oxygen is normally minus 2. Four oxygens contribute minus 8 total. For the overall charge of minus 2, sulfur must be plus 6, since plus 6 plus minus 8 equals minus 2.
Simple analogy
Think of apply oxidation number assignment like following a short checklist: identify the clue, confirm the rule, and then make the move that fits this exact scenario.
How to review it before a retake
- Underline the command word and name what the question is asking before rereading the choices.
- Compare the correct answer against the closest distractor and write the exact detail that separates them.
- Retest this objective with a fresh question without looking at the rationale first.