show covalent bonding for O + O (O2)

Question

 show how covalent bonding occurs for:

1. H + H (H2)

 

2. O + O (O2)

 

3. N + N (N2)

 

4. C+ O (CO2)

 

5. H + O (H2O)

Answer 1

To show how covalent bonding occurs in O₂ using Lewis dot structures, you need to follow a few steps:

1. Identify the number of valence electrons each atom in the molecule has. You can find this number by consulting a periodic table and looking at the column numbers at the top. Oxygen is in group 16 or 6A, and therefore has 6 valence electrons for each oxygen atom. The molecule O₂ has 12 valence electrons, which will exist as a combination of bonding and non-bonding electrons.
2. Use a pair of electrons to connect the two oxygen atoms - this requires 2 electrons to make a bond, leaving you with 10 valence electrons to distribute.
3. Distribute the remaining electrons as lone pairs until you have accounted for all 10 remaining valence electrons. You will end up with one oxygen bearing two lone pairs, one oxygen bearing 3 lone pairs, and a pair of electrons connecting the two atoms.
4. Each oxygen needs a full octet to remain uncharged. To accomplish this, one of the lone pairs on the oxygen with three lone pairs will become a bonding pair, becoming a second set of electrons connecting the two atoms. This allows both oxygens to have a full octet and a neutral formal charge.
5. The final structure will be two oxygens double-bonded together via two pairs of electrons. Each oxygen atom bears two lone pairs.