Given below are two statements : Statement (I) : The radii of isoelectronic species increases in the order: mathrm M g ^ 2 + < mathrm N a ^ + < mathrm F ^ - < mathrm O ^ 2 -$\mathrm {M g} ^ {2 +} < \mathrm {N a} ^ {+} < \mathrm {F} ^ {-} < \mathrm {O} ^ {2 -}$ Statement (II) : The magnitude of electron gain enthalpy of halogen decreases in the order: mathrm C l > mathrm F > mathrm B r > mathrm I$\mathrm {C l} > \mathrm {F} > \mathrm {B r} > \mathrm {I}$

### Core Logic Decode the IUPAC name "Unununnium" into its atomic number. Un = 1 Un = 1 Un = 1 Suffix = ium So, the atomic number is 111. ### Step 1: Finding group number For d-block elements with Z > 100, the group number is the last two digits of the atomic number. Since Z = 111, the element belongs to group 11 (the Copper group). ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties

### Core Logic From the grid layout, A^prime$A^\prime$ and B^prime$B^\prime$ are in the same period (left to right), while C^prime$C^\prime$ and D^prime$D^\prime$ are below them in the next period. In general, moving along a period from left to right, size decreases and metallic character decreases. Moving down a group, size increases and metallic character increases. Atomic Radii / Size: B^prime < A^prime$B^\prime < A^\prime$ (across period) D^prime < C^prime$D^\prime < C^\prime$ (across period) A^prime < C^prime$A^\prime < C^\prime$ and B^prime < D^prime$B^\prime < D^\prime$ (down the group) Combining them: B^prime < A^prime < D^prime < C^prime$B^\prime < A^\prime < D^\prime < C^\prime$. (Statement A is correct, C is incorrect). Metallic Character: B^prime < A^prime$B^\prime < A^\prime$ and D^prime < C^prime$D^\prime < C^\prime$ Overall trend follows size closely for these blocks: B^prime < A^prime < D^prime < C^prime$B^\prime < A^\prime < D^\prime < C^\prime$. (Statement B is correct). Ionic Radii (+$+$ ions): Follows the same basic trend as atomic radii: B^prime + < A^prime + < D^prime + < C^prime +$B^{\prime +} < A^{\prime +} < D^{\prime +} < C^{\prime +}$. (Statement D is correct). ### Step 1: Final Selection Statements A, B, and D are correct. Statement C contradicts A, so it is incorrect. Option 2 is the right choice. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties

### Core Logic Electron gain enthalpy (Delta_egH$\Delta_{eg}H$) values are considered with their signs when ordering from largest to smallest algebraically. Arranging these algebraically from highest to lowest: +96 > -200 > -325 > -333$+96 > -200 > -325 > -333$ Thus, Ar > S > Br > F$Ar > S > Br > F$, which corresponds to A > D > B > C$A > D > B > C$. ### Pattern Recognition Noble gases always have positive electron gain enthalpies (highest algebraically). Halogens have highly negative values (lowest algebraically). Fluorine is highly negative, Bromine is slightly less negative. Sulfur sits in between. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Classification of Elements and Periodicity in Properties