### Related Formula \text{Anomalous properties of second-period elements.} ### Core Logic The anomalous properties of oxygen compared to other chalcogens stem directly from its position in the second period of the periodic table. It is characterized by: 1. An exceptionally **small atomic radius**. 2. Highly pronounced **electronegativity**. 3. Complete absence of low-energy valence d$d$-orbitals. ### Step 1: Selection Verification Therefore, the combination of small size and high electronegativity is the correct choice, matching option (3). ### Pattern Recognition All first members of periodic blocks (textN$\text{N}$, textO$\text{O}$, textF$\text{F}$) deviate significantly from their heavier group members due to their high charge density, high electronegativity, and lack of d$d$-orbitals. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: p-Block Elements

### Core Logic Boron forms a highly compact, robust icosahedral covalent polymeric three-dimensional framework structure (B_12$B_{12}$ units). This extremely solid, dense crystalline lattice organization requires immense thermal activation energy to rupture, explaining why its melting point (2453text K$2453\text{ K}$) is uniquely elevated among Group 13 elements. Both statements are true and (R) is the perfect explanation. ### Chapter Mix Class 11 Chemistry: p-Block Elements

### Step 1: Audit oxidation numbers individually ### Step 2: Sum the targets The compounds displaying an exact +4$+4$ assignment are textH_2textSO_3$\text{H}_2\text{SO}_3$, textSOCl_2$\text{SOCl}_2$, and textSF_4$\text{SF}_4$. The total number is 3. ### Pattern Recognition Sulfurous derivatives, thionyl groupings, and tetrafluoride configurations typically feature the +4$+4$ oxidation level state. ### Chapter Mix Class 11 Chemistry: Redox Reactions Class 12 Chemistry: p-Block Elements

### Core Logic **Analyzing Statement I:** The electronegativity values for Group 14 elements according to the Pauling scale are approximately: - Carbon (C): 2.5$2.5$ - Silicon (Si): 1.8$1.8$ - Germanium (Ge): 1.8$1.8$ - Tin (Sn): 1.8$1.8$ - Lead (Pb): 1.9$1.9$ The electronegativity values from Si to Pb are almost identical, and it slightly increases at Pb due to the poor shielding effect of d and f-orbitals (inert pair effect). It does not "gradually decrease." Therefore, Statement I is false. **Analyzing Statement II:** Group 14 consists of: - Carbon (C): Non-metal - Silicon (Si) & Germanium (Ge): Metalloids - Tin (Sn) & Lead (Pb): Metals Therefore, the group contains non-metals, metalloids, and metals. Statement II is true. ### Step 1: Final Conclusion Statement I is false, but Statement II is true. ### Pattern Recognition Electronegativity in Group 13 and 14 does not follow a strict linear decrease due to d-block and f-block contraction (poor shielding by d and f electrons). ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: The p Block Elements

### Core Logic As we move down Group 16, the atomic size of the central atom increases. The increased size of Tellurium compared to Sulphur leads to a longer and weaker Element-Hydrogen bond. Consequently, the bond dissociation enthalpy of H_2Te$H_2Te$ is lower than that of H_2S$H_2S$. Because the Te-H$Te-H$ bond is weaker and more easily broken, it ionizes to release H^+$H^+$ ions more readily than H_2S$H_2S$. Thus, H_2Te$H_2Te$ is more acidic than H_2S$H_2S$, making both the assertion and reason true, with the reason correctly explaining the assertion. ### Pattern Recognition Down the group for p-block hydrides: Size increases → Bond length increases → Bond strength decreases → Acidity increases. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: The p Block Elements