#### Answer

Solutions for problem 1.1

#### Work Step by Step

$a)$ 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 $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$