Chemistry - PERIODIC TABLE Question with Solution | TestHub

(A) is correct because metallic character increases down a group and decreases from left to right across a period.

(B) is correct because for isoelectronic species (all having 10 electrons), ionic radius increases as the nuclear charge decreases.

(C) is incorrect because the correct order for second ionization energy is $Li>O>F>N>C>Be>B$ due to the stability of the resulting electronic configurations.

(D) is correct because smaller ions ($L{i}^{+}$) undergo heavier hydration in water, making them bulky and reducing their ionic mobility compared to larger ions ($C{s}^{+}$).