The ionic radii in an isoelectronic series containing ten electrons are listed below
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
The ionic radii in an isoelectronic series containing ten electrons are listed below. All radii were determined using the same method under identical conditions.
O²⁻ 140 pm F⁻ 133 pm Na⁺ 98 pm Mg²⁺ 72 pm Al³⁺ 53 pm Xⁿ⁺ 37 pm
Address the following tasks concerning the unidentified cation Xⁿ⁺.
(a) Determine the charge n on the cation Xⁿ⁺ and state the atomic number of the neutral atom from which it is derived.
(b) Identify element X by name and write its complete ground-state electron configuration.
(c) Rank the six species in the series from smallest to largest ionic radius. Explain how both nuclear charge and electron–electron repulsions govern the trend you observe.
(d) The oxide of X in its common oxidation state forms a solid network compound. Compare qualitatively the lattice energy of this oxide to that of Al₂O₃, giving two distinct factors that account for any difference.