Isomers

Question 1

Isomer

Answer 1

same molecular formula; different structures of a molecule

Question 2

Difference between isomer and resonance structure

Answer 2

An isomers have a different arrangement of both electrons AND atoms, while resonance structures have a different arrangement of electrons only

Question 3

What does IHD stand for?

Answer 3

Index of Hydrogen Deficiency

Question 4

What is the purpose of IHD?

Answer 4

Tells us the number of rings and/or pi bonds in a structure

Question 5

Formula for IHD

Answer 5

(2n+2)-total # of hydrogens/2
n=number of carbons

Question 6

Saturated molecules

Answer 6

have maximum number of hydrogens

Question 7

Unsaturated molecules

Answer 7

make pi bond/ring and lose 2 hydrogens

Question 8

Calculating IHD when structure is given

Answer 8

Count the number of rings and pi bonds

Question 9

Pi bonds

Answer 9

double bond= 1 pi bond, 1 sigma bond
triple bond= 1 sigma bond, 2 pi bonds

Question 10

Constitutional isomers

Answer 10

Have the same molecular formula but different connectivity

Question 11

Conformational isomers (stereoisomers)

Answer 11

Have the same molecular formula AND same connectivity, but different orientation in space

Question 12

Types of stereoisomer (conformational isomers)

Answer 12

Geometric isomers (cis/trans)

Question 13

Cis/trans isomers

Answer 13

differ in geometry of groups on a double bond

Question 14

Cis stereoisomers

Answer 14

have similar groups on the same side

Question 15

Trans isomers

Answer 15

have similar groups on opposite sides

Question 16

How do you determine if stereoisomer is cis or trans?

Answer 16

split the molecule down the double bond to determine if cis or trans