Chemguide: Support for CIE A level Chemistry
Learning outcome 13
13.4: Isomerism: structural and stereoisomerism
Statements 13.4.2, 13.4.3 and 13.4.5
These statements talk about cis-trans isomerism, a form of stereoisomerism.
Before you go on, you should find and read the statement in your copy of the syllabus.
You will find this discussed in detail on the page about geometric isomerism. Geometric isomerism is an alternative name for cis-trans isomerism. The latest name is E-Z isomerism.
For the current CIE syllabus, you do not need to know anything about the E-Z system.
You do not need the detailed explanation at the bottom of the page about the physical properties of cis-trans isomers. However, you should know that cis and trans isomers will have slightly different melting and boiling points. This bit of knowledge came up as a part of a multiple choice question in the past, despite there being no specific mention of it in the syllabus.
You could read this section if you were interested, but you won't be examined on it.
Notice the possibility of geometric isomers in a ring compound. You need it for statement 13.4.5.
© Jim Clark 2020