NaimExplain

What is the percent "s" character of the hybrid oxygen orbital in water? 25% When orbitals hybridize they do so in a weighted manner such that the character of the hybrid orbital is an average of its contributors. Therefore, an sp hybrid orbital has 50% s character and 50% p character. By this same logic, the oxygen in water—which is sp3 hybridized, exhibits 25% "s" character and 75% p character. Mathematically, 1s orbital and 3p orbital's equal 4 orbitals (1s + 3p = 4 orbitals). 1 out of 4, ¼ , or 25% is from the s orbital.

How does the rotational limitation of pi bonds relate to proteins? The amide functional group in a protein (created when the amino group of one amino acid attacks the carboxylic acid group of another amino acid) exhibits resonance and therefore both the C-O and C-N bonds have double-bond character. This prevents rotation—a key characteristic of peptide bonds.

Which is stronger, a sigma bond, or a pi bond? Why? Sigma bonds are significantly stronger than pi bonds. This is because sigma bonds allow for electron density to be concentrated to a much larger degree between the two nuclei. The lowest energy state for electrons—being electrostatically attracted to both nuclei simultaneously, is between those two nuclei and as close to each core as possible. In a pi bond the p orbitals overlap above and below the atom, localizing the electrons above and below the plane of the bond—a higher energy state compared to the head-on overlap of a sigma bond. You can also conceptualize that pi bonds are weaker simply because we know those electrons are in a higher-energy state. It is universally true that when a bond is higher in energy it will require less energy to break it.