Classification of Elements and Periodicity in Properties
Test 11

Boiling point of group 14 tetrachlorides (\(\ce{XCl4}\)) increases with molecular weight due to stronger London forces. \(\ce{SnCl4}\) (Sn, heaviest) has the highest boiling point among C, Si, Ge, and Sn.

In group 13, Ga and In have a smaller ionization enthalpy difference due to d-block contraction effects, unlike B-Al, where the drop is larger due to a new shell.

Solubility of group 2 oxides decreases down the group as lattice energy dominates over hydration energy. \(\ce{BaO}\) (largest cation) is the least soluble among BeO, MgO, CaO, and BaO.

In group 14, Ge is a metalloid, while C (non-metal), Sn (metal), and Pb (metal) are not.

For isoelectronic species (\(\ce{N^3-}\), \(\ce{O^2-}\), \(\ce{F^-}\), \(\ce{Na+}\), all with 10 electrons), radius increases with decreasing nuclear charge. \(\ce{N^3-}\) (Z=7) has the largest radius.

Atomic radius increases down a group, with the largest jump often between early periods. In group 1, Li (period 2) to Na (period 3) shows a significant increase due to the addition of a new shell, compared to later pairs.

Total electrons = 18, corresponding to Ar (period 3, group 18). Others: Cl (17 electrons), K (19 electrons), S (16 electrons).

Group 15 elements (N, P, As, etc.) form hydrides like \(\ce{NH3}\). \(\ce{CH4}\) (group 14), \(\ce{H2O}\) (group 16), and \(\ce{HCl}\) (group 17) are from other groups.

f-block elements have electrons filling \(f\)-orbitals (lanthanoids and actinoids). Ce (Z=58) is an f-block element, while Sc (d-block), Rb (s-block), and Xe (p-block) are not.

Noble gases (group 18) have a complete valence shell. Among He, Ne, Ar, and Kr, all are noble gases, but He is the simplest with \(1s^2\). Here, He is the correct choice based on options.