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Chemistry Question 71 – NEET-UG 2024

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Among Group 16 elements, which one does NOT show −2 oxidation state?

Recall the general trend of oxidation states and metallic character within Group 16 elements (chalcogens).

Step 1: Identify Group 16 Elements and General Oxidation State✦ Active

Group 16 elements (chalcogens) include Oxygen (O), Sulfur (S), Selenium (Se), Tellurium (Te), and Polonium (Po). They have 6 valence electrons and typically exhibit a −2 oxidation state by gaining two electrons to achieve a stable octet.

Step 2: Analyze Trend in Group 16○ Expand

As we move down Group 16, the metallic character of the elements increases, and their electronegativity decreases. This trend implies that the tendency to gain electrons and form a stable −2 oxidation state diminishes from Oxygen to Polonium.

💡 Teacher's Secret Hint

Remember that metallic character increases down a group, making elements less likely to gain electrons.

Step 3: Evaluate Options for -2 Oxidation State○ Expand

Oxygen (O) is highly electronegative and commonly shows a −2 oxidation state (e.g., in H2O, CO2). Selenium (Se) and Tellurium (Te) are metalloids and also commonly exhibit a −2 oxidation state (e.g., in H2Se, H2Te). Polonium (Po), being the heaviest and most metallic element in Group 16, primarily exhibits positive oxidation states (e.g., +2, +4) due to its metallic character and lower electronegativity. It rarely, if ever, forms a stable −2 oxidation state.

💡 Teacher's Secret Hint

Polonium's metallic nature makes it prefer losing electrons rather than gaining them to achieve a −2 state.

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