Write electron configurations for a. the cations \(\mathrm{Mg}^{2+}, \mathrm{K}^{+},\) and \(\mathrm{Al}^{3+}\) . b. the anions \(\mathrm{N}^{3-}, \mathrm{O}^{2-}, \mathrm{F}^{-},\) and \(\mathrm{Te}^{2-}\)

To write the electron configurations for the cations \(\mathrm{Mg}^{2+}, \mathrm{K}^{+}, \mathrm{Al}^{3+}\), we start by finding the electron configurations for neutral Mg, K, and Al atoms, and then remove the necessary electrons to account for the charge. a. Mg has 12 protons and 12 electrons in a neutral atom: \[1s^2 2s^2 2p^6 3s^2\] Since \(\mathrm{Mg}^{2+}\) has lost two electrons, the electron configuration for \(\mathrm{Mg}^{2+}\) will be: \[1s^2 2s^2 2p^6\] b. K has 19 protons and 19 electrons in a neutral atom: \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^1\] Since \(\mathrm{K}^{+}\) has lost one electron, the electron configuration for \(\mathrm{K}^{+}\) will be: \[1s^2 2s^2 2p^6 3s^2 3p^6\] c. Al has 13 protons and 13 electrons in a neutral atom: \[1s^2 2s^2 2p^6 3s^2 3p^1\] Since \(\mathrm{Al}^{3+}\) has lost three electrons, the electron configuration for \(\mathrm{Al}^{3+}\) will be: \[1s^2 2s^2 2p^6\]

To write the electron configurations for the anions \(\mathrm{N}^{3-}, \mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Te}^{2-}\), we start by finding the electron configurations for neutral N, O, F, and Te atoms, and then add the necessary electrons to account for the charge. a. N has 7 protons and 7 electrons in a neutral atom: \[1s^2 2s^2 2p^3\] Since \(\mathrm{N}^{3-}\) has gained three electrons, the electron configuration for \(\mathrm{N}^{3-}\) will be: \[1s^2 2s^2 2p^6\] b. O has 8 protons and 8 electrons in a neutral atom: \[1s^2 2s^2 2p^4\] Since \(\mathrm{O}^{2-}\) has gained two electrons, the electron configuration for \(\mathrm{O}^{2-}\) will be: \[1s^2 2s^2 2p^6\] c. F has 9 protons and 9 electrons in a neutral atom: \[1s^2 2s^2 2p^5\] Since \(\mathrm{F}^{-}\) has gained one electron, the electron configuration for \(\mathrm{F}^{-}\) will be: \[1s^2 2s^2 2p^6\] d. Te has 52 protons and 52 electrons in a neutral atom: \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^4\] Since \(\mathrm{Te}^{2-}\) has gained two electrons, the electron configuration for \(\mathrm{Te}^{2-}\) will be: \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6\]