Outermost electronic configuration of a group 13 element, E, is 4s², 4p¹. The electronic configuration of an element of p-block period-five placed diagonally to element, E is :

Metallic sodium does not react normally with :

Spin only magnetic moment of an octahedral complex of Fe²⁺ in the presence of a strong field ligand in BM is :

Which one of the following species doesn't have a magnetic moment of 1.73 BM, (spin only value)?