Which of the following ions have noble gas electron configurations? a. \(\mathrm{Fe}^{2+}, \mathrm{Fe}^{3+}, \mathrm{Sc}^{3+}, \mathrm{Co}^{3+}\) b. \(\mathrm{Tl}^{+}, \mathrm{Te}^{2-}, \mathrm{Cr}^{3+}\) c. \(\mathrm{Pu}^{4+}, \mathrm{Ce}^{4+}, \mathrm{Ti}^{4+}\) d. \(\mathrm{Ba}^{2+}, \mathrm{Pt}^{2+}, \mathrm{Mn}^{2+}\)

Check if the ion's electron configuration matches the electron configuration of the nearest noble gas. If the match, the ion has a noble gas configuration. a. \(\mathrm{Fe}^{2+}, \mathrm{Fe}^{3+}, \mathrm{Sc}^{3+}, \mathrm{Co}^{3+}\) - \(\mathrm{Fe}^{2+}\): \([Ar] 3d^6\), it doesn't match any noble gas configuration. - \(\mathrm{Fe}^{3+}\): \([Ar] 3d^5\), it doesn't match any noble gas configuration. - \(\mathrm{Sc}^{3+}\): \([Ar]\), it matches noble gas electron configuration of the element Ar (Argon). - \(\mathrm{Co}^{3+}\): \([Ar] 3d^6\), it doesn't match any noble gas configuration. b. \(\mathrm{Tl}^{+}, \mathrm{Te}^{2-}, \mathrm{Cr}^{3+}\) - \(\mathrm{Tl}^{+}\): \([Xe] 4f^{14} 5d^{10} 6s^2\), it matches noble gas electron configuration of the element Xe (Xenon). - \(\mathrm{Te}^{2-}\): \([Kr] 5s^2 4d^{10} 5p^6\), it matches noble gas electron configuration of the element Kr (Krypton). - \(\mathrm{Cr}^{3+}\): \([Ar] 3d^3\), it doesn't match any noble gas configuration. c. \(\mathrm{Pu}^{4+}, \mathrm{Ce}^{4+}, \mathrm{Ti}^{4+}\) - \(\mathrm{Pu}^{4+}\): \([Rn] 5f^2\), it doesn't match any noble gas configuration. - \(\mathrm{Ce}^{4+}\): \([Kr] 4d^{10}\), it matches noble gas electron configuration of the element Kr (Krypton). - \(\mathrm{Ti}^{4+}\): \([Ar]\), it matches noble gas electron configuration of the element Ar (Argon). d. \(\mathrm{Ba}^{2+}, \mathrm{Pt}^{2+}, \mathrm{Mn}^{2+}\) - \(\mathrm{Ba}^{2+}\): \([Xe]\), it matches noble gas electron configuration of the element Xe (Xenon). - \(\mathrm{Pt}^{2+}\): \([Xe] 4f^{14} 5d^8\), it doesn't match any noble gas configuration. - \(\mathrm{Mn}^{2+}\): \([Ar] 3d^5\), it doesn't match any noble gas configuration. So, the ions with noble gas electron configurations are \(\mathrm{Sc}^{3+}, \mathrm{Tl}^{+}, \mathrm{Te}^{2-}, \mathrm{Ce}^{4+}, \mathrm{Ti}^{4+}\) and \(\mathrm{Ba}^{2+}\).