(i) Mention any two anomalous properties of second period elements. (ii) Arrange Na^(+), Mg^(2+) and Al^(3+) in the increasing order of ionic radii. Gove reason.

(i) Mention any two anomalous properties of second period elements. (

1.	(i) Mention any two anomalous properties of second period elements. (ii) Arrange Na^(+), Mg^(2+) and Al^(3+) in the increasing order of ionic radii. Gove reason.
Answer» Solution :(i) Anomalous properties of SECOND period elements: 1. In the `1^(st)` group, lithium forms compounds with more covalent character while the other elements of this group form only ionic compounds. 2. In the `2^(nd)` group, beryllium forms compounds with more covalent character while the other elements of this family form only ionic compounds. (ii) `Na^(+), Mg^(2+)` and `Al^(3+)` are ISOELECTRONIC cations. The CATION with the greater positive charge will have a smaller radius because of the greater ATTRACTION of the electrons to the nucleus. Hence the increasing order of ionic radii is, `r_(Na^(+)) gt r_(Mg^(2+)) gt r_(Al^(3+))`.