Introduction to Biochemistry - Quiz 1.1.1

Starting this post the results are validated by EDX, so I am sure these answers are correct.

Iron and silicon are available in living organism only for trace amount (arguably - while Iron is in trace amount, it is an important element for human - we need it for hemoglobin). But we have abundant amount of iron and silicon in Earth's crust.

$ sp^3 $ orbitals are formed by merging the s orbital with 3 p orbitals, therefore we have 4 $ sp^3 $ orbitals. These 4 $ sp^3 $ orbital are then used to form 4 different bonds with 4 different atoms.

$ sp^3 $ orbitals are formed by merging the s orbital with 2 p orbitals, therefore we have 3 $ sp^3 $ orbitals. These 3 $ sp^3 $ orbital are then used to form 3 different bonds with 3 different atoms. For one particular bond, the associated $ p $ orbital will also overlap and share electrons, that is a double bond.

$ sp^2 $ orbitals are formed by merging the s orbital with 1 p orbitals, therefore we have 2 $ sp^3 $ orbitals. These 2 $ sp^3 $ orbital are then used to form 2 different bonds with 2 different atoms. For on3 particular bond, the other two$ p $ orbitals will also overlap and share electrons, that is a triple bond.

First of all $ \Delta EN $ is the difference in electronegativity. The $ C-C $ bond is obviously neutral. Now, we analyze the electronegativity of $ C $, $ N $ and $ O $, obviously, $ O $ is the most electronegative, therefore $ O-H $ has the biggest difference in electronegativity.