Chemistry S & P Block Elements UHS 2023
PMDC Verified Question 24 of 104
Oxidation number of free magnesium is?
A
0
B
+1
C
+2
D
+3
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 0
Concept:

The oxidation state rules for elements in their standard, uncombined states.

Solution:

  • By definition, the oxidation number of an atom in its pure, free, uncombined elemental state is exactly zero.
  • This is because in a pure element, all atoms are identical; there is no difference in electronegativity, so electrons are not pulled toward one atom or another.
  • Therefore, free solid Magnesium metal (\( \text{Mg}_{(s)} \)) has an oxidation state of 0.


Why other options are incorrect:

  • +2: This is the oxidation state of Magnesium after it has reacted and formed a compound (like \( \text{MgCl}_2 \)), not when it is free.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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