Isomers

• What are isomers?

  Compounds with the same molecular formula
• How do structural isomers differ from each other?

  They have different atom arrangements
• What are the types of structural isomers?

  • Chain isomers
  • Position isomers
  • Functional group isomers
• What distinguishes chain isomers?

  Different arrangements of the carbon skeleton
• What is an example of chain isomerism?

  Methylpropane and butane
• What is the molecular formula for butane and methylpropane?

  C₄H₁₀
• What are position isomers?

  Isomers differing in functional group position
• What is the molecular formula for 1-fluorobutane and 2-fluorobutane?

  C₄H₉F
• What is an example of functional group isomerism?

  Propanal and propanone
• How do propanal and propanone differ?

  They have different functional groups
• What type of isomerism occurs in alkenes?

  E/Z isomerism
• What is the significance of the double bond in alkenes?

  It prevents free rotation around the bond
• What is the geometry of alkenes?

  Trigonal planar with bond angles of 120°
• What does E stand for in E/Z isomerism?

  Opposite sides of the double bond
• What does Z stand for in E/Z isomerism?

  Same sides of the double bond
• What is the definition of isomers?

  Isomers are compounds that have the same molecular formula but their atoms are arranged in different ways
• How can the difference in structure of isomers lead to variations in their physical and chemical properties?

  The difference in structure of isomers can lead to variations in their physical and chemical properties
• What are the main types of structural isomers?

  The main types of structural isomers are: chain isomers, position isomers, and functional group isomers
• How do chain isomers differ from each other?

  Chain isomers differ in the arrangement of the carbon skeleton, such as straight chains vs. branched chains
• What is the difference between 1-fluorobutane and 2-fluorobutane?

  1-fluorobutane and 2-fluorobutane are position isomers, where the fluorine atom is attached to different carbon positions on the chain
• How do propanal and propanone differ as functional group isomers?

  Propanal is an aldehyde while propanone is a ketone, despite having the same molecular formula of C₃H₆O
• What is the definition of stereoisomers?

  Stereoisomers are compounds with the same structural formula but different spatial arrangements of atoms
• Why do alkenes have a rigid, planar double bond that prevents free rotation?

  The double bond in alkenes is rigid and planar, preventing free rotation around the bond, which allows for the existence of different spatial arrangements of the attached groups
• What do the terms "E" and "Z" stand for in E/Z isomerism?

  E stands for the German word "entgegen" meaning "opposite", and Z stands for the German word "zusammen" meaning "together"
• How do the E and Z isomers of but-2-ene differ in the arrangement of the methyl groups?

  In E-but-2-ene, the two methyl groups are on opposite sides of the double bond, while in Z-but-2-ene, the two methyl groups are on the same side of the double bond
• What are the Cahn-Ingold-Prelog (CIP) priority rules?

  The CIP priority rules are guidelines for assigning priority to groups attached to double-bonded carbons, which is crucial for determining the configurations of stereoisomers, including E/Z isomers
• How do the CIP priority rules work?

  The CIP priority rules involve: 1) Identifying the atoms directly attached to the double-bonded carbons, 2) Assigning priorities based on atomic number, with the highest atomic number getting the highest priority, and 3) Considering the next set of atoms if there is a tie
• Who developed the Cahn-Ingold-Prelog (CIP) priority rules?

  The Cahn-Ingold-Prelog (CIP) priority rules were developed by Sir Christopher Ingold, along with Robert Sidney Cahn and Vladimir Prelog
• Determine the configuration (E or Z) of the molecule 1-bromo-1-fluoro-2-chloroethene based on the CIP priority rules.

  This molecule is the Z isomer because the highest priority groups (Br and Cl) are on the same side of the double bond
• Determine the configuration (E or Z) of the molecule 1-bromo-1-fluoro-2-chloroethene based on the CIP priority rules.

  This molecule is the E isomer because the highest priority groups (Br and Cl) are on opposite sides of the double bond
• What are the key differences between E and Z isomers?

  • E isomers have the highest priority groups on opposite sides of the double bond
  • Z isomers have the highest priority groups on the same side of the double bond
  • E isomers have a trans-like configuration, while Z isomers have a cis-like configuration
  • The arrangement of the highest priority groups determines the E/Z configuration