# Question #7a649

For example, hydrogen has one electron in the s-orbital of the first shell, so its configuration is written 1${s}^{1}$ Lithium has two electrons in the 1s-subshell and one in the (higher-energy) 2s-subshell, so its configuration is written 1${s}^{2}$ 2${s}^{1}$ (pronounced "one-s-two, two-s-one"). Phosphorus (atomic number 15) is as follows: 1${s}^{2}$ 2${s}^{2}$ 2${p}^{6}$ 3${s}^{2}$ 3${p}^{3}$.