# How do electron configurations affect properties and trends of a compound?

An oxygen atom has a $2 {p}^{4}$ configuration in the valence shell, which means that two electrons are unpaired, and it can form bonds to two other atoms (e.g., ${H}_{2} O$) or two bonds to one other atom (e.g., ${O}_{2}$).
Carbon has a $2 {s}^{2} 2 {p}^{2}$ electron configuration (2 unpaired electrons), and in this configuration it can bind to two other atoms (e.g., $C {H}_{2}$ radical). But another low-energy configuration, $2 {s}^{1} 2 {p}^{3}$, has 4 unpaired electrons and can bind to 4 other atoms (e.g., $C {H}_{4}$). which is usually much more energetically favorable.