Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
12 Cards in this Set
- Front
- Back
|
What is the process for assigning formal charge to atoms of a molecular ion? |
1. Write down group # of atom. 2. Determine valence electron count: add # unshared valence electrons to number of bonds to that atom. 3. Subtract 2 from 1. This is the formal charge. It can be positive or negative. |
|
|
Three generalizations about bond length (in order of most to least important).... |
1. Bond lengths increase significantly toward higher (farther down, higher refers to #, not coordinates) periods of the periodic table . For example, bond lengths for row 5 will usually be longer than for row 3. 2. Bond lengths decrease with increasing bond order (bond order is the number of bonds between atoms). 3. Bonds of a given order decrease in length toward higher atomic number along a given period of the table. |
|
|
What defines Diastereomers? |
Stereoisomers that are not mirror images of one another and are non-superimposable on one another. |
|
|
What are Epimers? |
Diastereomers that differ in the 3D configuration at one chiral center. |
|
|
What are the rules for assigning Chirality? |
STEP 1: The four different groups attached to the chiral center atom are ranked from highest priority (1) to lowest priority (4). Highest priority goes to the atom with the largest atomic #. STEP 2: Chiral center is reoriented so that the lowest priority group is placed in the back and the remaining groups are connected in order of priority. If these groups (1, 2, and 3) are in a clockwise order, then the chiral center is R. If the groups (1, 2, and 3) are in a counterclockwise order then the chiral center is S. |
|
|
How do you determine R or S configuration? |
Assign priority to constituent groups, then view the chiral center from the opposite side of the lowest priority constituent (often a Hydrogen). |
|
|
What is an enol? |
OH bonded to a carbon involved in a double bond to another carbon. Has the form HO-C=C-R |
|
|
How is the alpha carbon designated? |
It's the C that attaches to the C of a functional group. For example: in CH3-CH2-CHOH, the alpha carbon is bold. Note that there can be more than one alpha carbon. |
|
|
How is the beta carbon designated? |
It's the second carbon away from the functional group carbon, and is separated from the functional group by the alpha carbon. There can be more than one beta carbon. |
|
|
What are epimers? |
Epimers are diastereomers that contain more than one chiral center but differ from each other in the absolute configuration at only one chiral center. |
|
|
What are diastereomers? |
Diastereomers are stereoisomers that are not related as object and mirror image and are not enantiomers. |
|
|
What's the max # of optically active stereoisomers for a molecule? |
2^n, where n = # of chiral centers |
