- O-O single bonds and H-O single bonds in [tex]\text{H}_2\text{O}_2[/tex] molecules.
- H-O single bonds in [tex]\text{H}_2\text{O}[/tex] molecules.
- O=O double bonds in [tex]\text{O}_2[/tex] molecules.
Explanation
How many valence electrons do atoms in each molecule need for them to be stable?
- Each H atom needs two valence electrons to be stable.
- Each atom of an element other than H needs eight valence electron to be stable.
- There are two H atoms and two O atoms in an [tex]\text{H}_2\text{O}_2[/tex] molecule. Atoms in each [tex]\text{H}_2\text{O}_2[/tex] need [tex]2 \times 1 + 2\times 2 = 6[/tex] more electrons to be stable.
- There are two H atoms and one O atom in an [tex]\text{H}_2\text{O}[/tex] molecule. Atoms in each [tex]\text{H}_2\text{O}[/tex] molecule need [tex]2 \times 1 + 2= 4[/tex] more electrons to be stable.
- There are two O atoms in an [tex]\text{O}_2[/tex] molecule. Atoms in each [tex]\text{O}_2[/tex] molecule need [tex]2 \times 2 = 4[/tex] more electrons to be stable.
How many chemical bonds in each molecule?
Each chemical bond adds one valence electron to each bonding atom. Each chemical bond connects two atoms. As a result, each chemical bond adds two valence electrons to the molecule.
- Each [tex]\text{H}_2\text{O}_2[/tex] molecule needs [tex]6 / 2 = 3[/tex] chemical bonds.
- Each [tex]\text{H}_2\text{O}[/tex] molecule needs [tex]4 / 2 = 2[/tex] chemical bonds.
- Each [tex]\text{O}_2[/tex] molecule needs [tex]4 /2= 2[/tex] chemical bonds.
What chemical bonds are these? Again, each H atom needs only one more valence electron to be stable. It will share only one electron with O and form one H-O bond. The rest of the chemical bonds are between O atoms.
- There are two H atoms in each [tex]\text{H}_2\text{O}_2[/tex] molecule, which form two H-O bonds. Two of the three chemical bonds in this molecule are H-O. The other is an O-O single bond between the two O atoms.
- There are two H atoms in each [tex]\text{H}_2\text{O}[/tex] molecule, which form two H-O bonds. Both chemical bonds in this molecule are H-O. There's no O-O bond in this molecule.
- There is no H atom in [tex]\text{O}_2[/tex] molecules. Both chemical bonds are between O atoms. However, there are only two O atoms. There must be two chemical bonds between the two O atoms. That bond will be an O-O double bond.
