Write electron configurations for a. the cations \(\mathrm{Sr}^{2+}, \mathrm{Cs}^{+}, \mathrm{In}^{+}\), and \(\mathrm{Pb}^{2+}\). b. the anions \(\mathrm{P}^{3-}, \mathrm{S}^{2-}\), and \(\mathrm{Br}^{-}\).

Note down the atom and its charge for the first cation or anion in the list. We'll start with the cation \(\mathrm{Sr}^{2+}\). ##Step 2: Determine Atomic Number##

Use the periodic table to find the atomic number of the atom. The atomic number of Sr (strontium) is 38. ##Step 3: Write Electron Configuration##

Use the periodic table to write the electron configuration for the neutral atom. The electron configuration of Sr is \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 5s^{2}\, 4d^{0}\] ##Step 4: Adjust Electron Configuration##

Since Sr has a charge of +2, we need to remove 2 electrons from the electron configuration. Removing the electrons from the outermost shell, we get the electron configuration for \(\mathrm{Sr}^{2+}\) as \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 4d^{0}\] Follow the same steps for all cations and anions given in the exercise: a. Electron configurations for the cations - \(\mathrm{Sr}^{2+}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 4d^{0}\] - \(\mathrm{Cs}^{+}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 5s^{2}\, 4d^{10}\, 5p^{6}\] - \(\mathrm{In}^{3+}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 4d^{10}\] - \(\mathrm{Pb}^{2+}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\, 5s^{2}\, 4d^{10}\, 5p^{6}\, 6s^{0}\, 4f^{14}\, 5d^{10}\] b. Electron configurations for the anions - \(\mathrm{P}^{3-}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\] - \(\mathrm{S}^{2-}\): \[1s^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\] - \(\mathrm{Br}^{-}\): \[1ss^{2}\, 2s^{2}\, 2p^{6}\, 3s^{2}\, 3p^{6}\, 4s^{2}\, 3d^{10}\, 4p^{6}\]