Chemistry Chapter 9: Organic Chemistry Basics

Question 1

Stereocenter

Answer 1

refers to any atom in a molecule that gives rise to stereoisomers when its substituents are rearranged or interchanged

Question 2

Are all stereocenters chiral?

Answer 2

NO. For example, CIS/Trans alkenes are stereocenters because rearranging the H and the methyl group produces a trans (so these are diastereomers)

Question 3

CIS/Trans are examples of what kind of isomerism?

Answer 3

Diastereomers

Question 4

Are all chiral centers also stereogenic?

Answer 4

YES

Question 5

Naming with E/Z

Answer 5

Each substituent on the double-bonded carbons is assigned a priority based on atomic number:
Higher atomic number = higher priority.
If there is a tie, you move outward along the chain until the tie is broken.

Question 6

Zaitsev’s rule states

Answer 6

that the more substituted alkene will form in preference to the less substituted molecule. So, generally, the more substituted a double bond is, the more stable the alkene will be.

more substituted = more stable

Question 7

Hückel’s Rule for Aromaticity

Answer 7

molecule is aromatic if it has (4n + 2) π-electrons, where n is any integer (0, 1, 2, 3, …).

Question 8

Conditions for Aromaticity:

Answer 8

For a molecule to be aromatic, it must satisfy all of these conditions:

Cyclic – The molecule must be a ring.
Planar – The ring must be flat (planarity allows π-electrons to delocalize).
Fully conjugated – Every atom in the ring must have a p-orbital, allowing continuous electron delocalization.
Follow Hückel’s rule – It must have (4n + 2) π-electrons.

Question 9

Constitutional isomers vs stereoisomers

Answer 9

Constitutional isomers: same formula different connectivity

Stereoisomers: same formula, same connectivity, different arrangement