Question

Atomic numbers of the group 13 elements are in the order B < Al < Ga < In < Tl. Arrange these elements in increasing order of ionic radii of M³⁺

Answer 1

• The given elements are in an increasing order of their atomic number
• The general outer electronic configuration of group 13 elements is ns² np¹
• M³⁺ ion is formed by the removal of three electrons from the outermost shell ‘n’.
• In the M³⁺ ions, the ‘n^-1’ shell becomes the outermost shell. Size of the ‘n^-1’ shell increases down the group

Therefore, the ionic radii of M³⁺ ion increases down the group in the following order: B³⁺ < Al³⁺ < Ga³⁺ < In³⁺ < Tl³⁺