Bonding sites

[Samin Kabir]

So in order to calculate the number of h bonding sites what do we need to do?

[Samin Kabir]

Follow up: why does Thymine have only 8 bonding sites? Shouldn't it be 12?

[Allan Nguyen 2G]

For hydrogen bonding, we know that a hydrogen bond can only occur between an H atom and a F, O, or N atom. When looking at thymine, we need to look at the amount of hydrogen atoms and the amount of lone pairs in any atom that is F, O, or N. In the thymine molecule, there's two hydrogen atoms, so that's two hydrogen bonding sites already. Now we need to look for the lone pairs, there are two lone pairs at the top for oxygen, a lone pair on the nitrogen on the right, two lone pairs for the oxygen atom in the bottom right, and a lone pair for the nitrogen on the bottom. This adds up to six lone pairs that can serve as hydrogen bonding sites as well as the two hydrogens that can also serve as hydrogen bonding sites. In total, there are 8 hydrogen bonding sites for thymine.