Anomalous Properties Of Second Period Elements, Diagonal Relationship, Important Topics For JEE Main 2024

Anomalous Properties Of Second Period Elements : The periodic table, a cornerstone of chemistry, arranges elements based on their atomic structure and properties. Among the numerous patterns and trends, the anomalous properties of second-period elements and the concept of diagonal relationships stand out as intriguing and essential phenomena.

Anomalous Properties Of Second Period Elements

Anomalous Properties of Second Period Elements : The second period of the periodic table comprises elements from lithium (Li) to neon (Ne). These elements exhibit distinctive characteristics that set them apart from other elements of the same group. One prominent feature is their small atomic size, resulting from the relatively low number of electron shells. Additionally, second-period elements possess higher electronegativity and ionization energy compared to elements in lower periods.

Diagonal Relationship

Diagonal Relationship: It has been observed that some elements of the second period show similarities with the elements of the third period placed diagonally to each other, though belonging to different groups. For example, lithium (of group 1) resembles magnesium (of group 2) and beryllium (of group 2) resembles aluminium (of group 13), and so as. This similarity in properties of elements placed diagonally to each other is called diagonal relationship.

The anomalous behaviour is due to their small size, large charge/ radius ratio and high electronegativity of the elements. In addition, the first member of group has only four valence orbitals (2s and 2p) available for bonding, whereas the second member of the groups have nine valence orbitals (3s, 3p, 3d). As a consequence of this, the maximum covalency of the first member of each group is 4