Answer:
It takes two electrons to make a covalent bond, one from each bonding atom. Lewis dot structures are one way to represent how atoms form covalent bonds. A table of Lewis dot symbols of nonmetal elements that form covalent bonds is shown in Fig. 2.28 Dots are placed around the symbol of the element to represent the number of valence electrons in the element. There can be up to eight dots, for eight valence electrons. The first four electrons are placed as single electrons, then the remaining four are paired.