## Organic Chemistry 9th Edition

$a)$ Oxygen has an atomic number of 8, and has a total of 8 electrons. So when filling in the proper order the ground state would be $1s^{2}2s^{2}2p^{4}$ $b)$ Nitrogen has an atomic number of 7, and has a total of 7 electrons. So when filling in the proper order the ground state would be $1s^{2}2s^{2}2p^{3}$ $c)$ Sulfur has an atomic number of 16, and has a total of 16 electrons. So when filling in the proper order the ground state would be $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$