Final answer:
The predicted formulas for the selenate and selenite ions are SeO4^2- and SeO3^2- respectively, based on their sulfur analogs, the sulfate (SO4^2-) and sulfite (SO3^2-) ions.
Step-by-step explanation:
The problem is asking to predict the formulas of ions that are analogs to those of the sulfur (S) oxyanions. Sulfur is in group 6A of the periodic table and forms multiple oxyanions, including the sulfate ion (SO42-) and the sulfite ion (SO32-). Since selenium (Se) is also in group 6A, we can predict its oxyanions would be similar.
(a) The selenate ion is the analog of the sulfate ion. Therefore, since sulfate is SO42-, selenate would replace S with Se and retain the same structure and oxidation state. The predicted formula for the selenate ion is SeO42-.
(b) Similarly, the selenite ion is the analog of the sulfite ion. Sulfite has the formula SO32-, so by analogy, the selenite ion would have the formula SeO32-.