Chapter 1: Organic Structures and Isomers

Chem 203

When it comes to writing condensed structures, what are the guidelines for doing so?

-ALL atoms are drawn

-Double bonds OMITTED

-Atoms drawn alongside to atom that they connect with

-Parentheses is used to group similar groups bonded to SAME ATOM

-Lone pairs OMITTED

Line formula and skeletal structures are interchangeable terms. What are the guidelines for following these structures?

-Carbon atoms are NOT shown. ASSUME a carbon is PRESENT where two lines MEET and at END of a line

-Hydrogens bonded to carbons are NOT shown; assume enough hydrogens are present so carbon has FOUR bonds

-Heteroatoms and any HYDROGENS bonded to them are shown

When line structures are used, sometimes “+” or “-” charges are shown. What do these mean?

-”+” charge indicates NO LONE PAIRS

-”-” charge indicates ONE lone PAIR

What are isomers?

Multiple Lewis structures representing the SAME molecular formula

What TWO categories can isomers be branched into?

Constitution/structural and stereoisomer

What is constitutional/structural isomer?

Different CONNECTIONS between atoms

What is stereoisomer?

SAME connection but different orientation in SPACE