Concept:Group IIA alkaline earth metals possess exactly two valence electrons. Due to their ionization energies and stable resulting noble gas configurations, they exclusively exhibit one oxidation state in compounds.
Formula:$$ Be \rightarrow Be^{2+} + 2e^- $$
Solution:- Beryllium (Be) is an alkaline earth metal (Group IIA). To achieve a stable electron configuration, it always loses its 2 valence electrons, forming a +2 oxidation state in all its known compounds.
- Halogens (like Chlorine and Bromine) can exhibit multiple oxidation states (e.g., -1, +1, +3, +5, +7) depending on the electronegativity of bonded atoms.
- Nitrogen also exhibits highly variable oxidation states ranging from -3 to +5.
Why other options are incorrect:As explained, N, Cl, and Br have highly variable oxidation states due to accessible d-orbitals (for Cl/Br) or multiple p-orbital bonding modes.
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