Covalent bonding occurs when atoms share electrons to achieve a stable electron configuration, typically a full outer shell.
Diagram 1: Hydrogen (H₂)
- Each hydrogen atom has 1 electron.
- They share their electrons so each atom effectively has 2 electrons (like Helium).
H • + • H → H : H (or H-H)
Diagram 2: Water (H₂O)
-
Oxygen needs 2 more electrons to complete its outer shell (it has 6).
-
Each hydrogen needs 1 more electron (they have 1).
-
Oxygen shares one electron with each hydrogen, and each hydrogen shares its electron with oxygen.
• •
:O:
• •
/
H• •H
becomes
• •
:O:
• •
/
H: :H
(The dots represent valence electrons. The 'H: :H' part shows the shared pairs forming covalent bonds.)