3.6 Covalent Bonding
FIGURE 3.10
Q:How many valence electrons does the oxygen atom (O) share with each hydrogen atom (H)? How many covalent
bonds hold the water molecule together?
A:The oxygen atom shares one pair of valence electrons with each hydrogen atom. Each pair of shared electrons
represents one covalent bond, so two covalent bonds hold the water molecule together.
The diagram in theFigure3.11 shows an example of covalent bonds between two atoms of the same element, in
this case two atoms of oxygen. The diagram represents an oxygen molecule, so it’s not a new compound. Oxygen
normally occurs in diatomic (“two-atom”) molecules. Several other elements also occur as diatomic molecules:
hydrogen, nitrogen, and all but one of the halogens (fluorine, chlorine, bromine, and iodine). At the URL below, you
can see an animation of electron sharing in a molecule of chlorine.
http://visservices.sdsc.edu/projects/discovery/ClCl_SD.mov
FIGURE 3.11
Q:How many electrons do these two oxygen atoms share? How many covalent bonds hold the oxygen molecule
together?
A:The two oxygen atoms share two pairs of electrons, so two covalent bonds hold the oxygen molecule together.