Cis-Trans Isomers and Covalent Bonds

This video tutorial introduces stereoisomers, focusing on geometrical isomers and the cis-trans naming system. It explains the difference between structural and stereoisomers, the conditions for cis-trans isomerism, and provides examples. The video also highlights the limitations of the cis-trans system and introduces the EZ system for more complex isomers.

What are stereoisomers?

• Molecules with different molecular formulas but same structural formulas.

• Molecules with the same structural formula but different arrangements in space.

• Molecules with different structural formulas and different arrangements in space.

• Molecules with the same molecular formula but different structural formulas.

What is a key characteristic of single covalent bonds?

• They are non-rotational.

• They have restricted rotation.

• They cannot flex.

• They are fully rotational.

Which of the following is true about double covalent bonds?

• They are weaker than single covalent bonds.

• They cannot flex at all.

• They are fully rotational.

• They have very restricted rotation.

What is the cis isomer of 1,2-dibromoethene?

• When both bromine atoms are on opposite sides.

• When both hydrogen atoms are on opposite sides.

• When both hydrogen atoms are on the same side.

• When both bromine atoms are on the same side.

What condition must be met for an alkene to have cis-trans isomers?

• The carbon atoms on the double bond must be attached to only hydrogen atoms.

• The carbon atoms on the double bond must be attached to two different groups.

• The carbon atoms on the double bond must be attached to identical groups.

• The carbon atoms on the double bond must be attached to only halogen atoms.

Why can't but-1-ene have cis-trans isomers?

• Because carbon one is bonded to two hydrogen atoms.

• Because it has a triple bond.

• Because it has a double bond.

• Because it has a single bond.

In but-2-ene, what determines the cis isomer?

• Both methyl groups are on the same side.

• Both hydrogen atoms are on the same side.

• Both halogen atoms are on the same side.

• Both carbon atoms are on the same side.

What is a limitation of the cis-trans naming system?

• It is only applicable to molecules with single bonds.

• It is only applicable to molecules with triple bonds.

• It can only be used for alkanes.

• It cannot be used when carbon atoms are bonded to four different groups.

What is the alternative naming system to cis-trans for geometrical isomers?

• The CD system.

• The E-Z system.

• The AB system.

• The XY system.

What is the main focus of the next video in the series?

• Study of single covalent bonds.

• Exploration of triple bonds.

• Detailed discussion on the E-Z system.

• Introduction to alkanes.