To draw the Lewis structure for water (H2O), we start by identifying the total number of valence electrons available.
Water consists of two hydrogen atoms and one oxygen atom. Hydrogen has one valence electron and oxygen has six. Thus, the total number of valence electrons is:
- 2 (from H) + 6 (from O) = 8 valence electrons
Next, we place the oxygen atom in the center since it is the more electronegative element. We then bond each hydrogen atom to the oxygen atom, using two electrons for each bond:
- O – H
- O – H
This accounts for 4 of the 8 total valence electrons.
Now, we need to complete the octet for the oxygen atom. Oxygen will share its remaining four electrons by forming two lone pairs:
- O::
At this point, the Lewis structure is completed. The hydrogen atoms are bonded to the oxygen atom, and the oxygen has two lone pairs, which provides the following representation:
This structure effectively shows the bond formation and the electron arrangement around the oxygen atom, giving us a clear understanding of the molecular geometry of water, which is bent due to the lone pairs on oxygen.