What are stereoisomers?

Why are alkenes able to form stereoisomers but alkanes cannot?

How do you differentiate between an E-isomer and a Z-isomer?

According to the Cahn-Ingold-Prelog priority rules, how is the highest priority group on each of the C=C carbons determined?

How would you determine the higher priority group when the atoms directly bonded to the carbon are the same?

Complete the sentences:
Cis-trans isomerism is a special type of E/Z isomerism where the two carbon atoms either side of the __________ bond have at least ______ group(s) in common. You can't use the cis-trans system if there are more than _____ different groups (other than ____________ atoms) attached around the double bond because you can't tell which isomer is which.

What is the difference between a cis- and a trans-isomer