91Ó°ÊÓ

For each element, find its atomic number from the periodic table. The atomic number indicates the number of protons and also the number of electrons in a neutral atom. \(\mathrm{Cl}\) - Chlorine has an atomic number of 17. \(\mathrm{Sb}\) - Antimony has an atomic number of 51. \(\mathrm{Sr}\) - Strontium has an atomic number of 38. \(\mathrm{W}\) - Tungsten has an atomic number of 74. \(\mathrm{Pb}\) - Lead has an atomic number of 82. \(\mathrm{Cf}\) - Californium has an atomic number of 98.

Remember the orbital filling order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p. Use this order to fill each atom's electrons into orbitals until the atom's total number of electrons is reached.

Using the atomic number and the orbital filling order, write the electron configuration for each element. \(\mathrm{Cl}\) (17 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^5}\) \(\mathrm{Sb}\) (51 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^{10}, 4p^6, 5s^2, 4d^{10}, 5p^3}\) \(\mathrm{Sr}\) (38 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^{10}, 4p^6, 5s^2}\) \(\mathrm{W}\) (74 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^{10}, 4p^6, 5s^2, 4d^{10}, 5p^6, 6s^2, 4f^{14}, 5d^4}\) \(\mathrm{Pb}\) (82 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^{10}, 4p^6, 5s^2, 4d^{10}, 5p^6, 6s^2, 4f^{14}, 5d^{10}, 6p^2}\) \(\mathrm{Cf}\) (98 electrons): \(\mathrm{1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^{10}, 4p^6, 5s^2, 4d^{10}, 5p^6, 6s^2, 4f^{14}, 5d^{10}, 6p^6, 7s^2, 5f^{10}}\) Note that these configurations assume a simple filling order based on the Aufbau principle. In some cases, electronic configurations can slightly differ from the order shown, but these are good approximate representations of the electronic structure for these elements.