Organic Chemistry Questionnaire PDF

TABLE OF CONTENTS Chapter 1: Intro to Orgo ………………………………………………………..…………X Topics Covered: Introduction to Organic Chemistry Carbon Valence Electrons Octet Rule Chapter 2: Drawing in Orgo …………………………………………………..………X Topics Covered: How to Draw Bonds Co...

TABLE OF CONTENTS Chapter 1: Intro to Orgo ………………………………………………………..…………X Topics Covered: Introduction to Organic Chemistry Carbon Valence Electrons Octet Rule Chapter 2: Drawing in Orgo …………………………………………………..………X Topics Covered: How to Draw Bonds Condensed Formula Conventional Structural Drawing Line-Angle Formula Chapter 3: Molecular Orbitals, Hybridization and Geometry ………..…………..X Topics Covered: Subshells Atomic Orbitals Hybridization Sigma and Pi bonds Geometry Bond Angles © COPYRIGHT*2013*STUDYORGO.COM*LCC* Chapter 4: Lewis Structures, Formal Charge and Resonance Structures …….X Topics Covered: What is a Lewis Structure? How do I draw a Lewis Structure? How do I figure out an atom’s formal charge? What is resonance? How do I figure out resonance problems? Major resonance vs. minor resonance Chapter 5: Basic Naming in Orgo- Naming Alkanes …………………………….X Topics Covered: Introduction to the concept of nomenclature in Organic Chemistry Step-by-step process for naming alkanes Chapter 6: Functional Groups ……………………………………………………………X Topics Covered: Introduction to functional groups Basic images of each functional group presente Chapter One: Intro to Orgo 1) What is Orgo? a. Organic chemistry, also known as “Orgo” or “O-Chem,” is the study of molecular structure and reactions pertaining to living matter. It is commonly referred to as the study of compounds that contain carbon. b. Why spend an entire year learning about carbon?!? i. Carbon containing compounds are the gateway to life. By studying organic chemistry one can have an appreciation for living organisms and the basis for life. One can also gain an understanding for organic chemistry contributions to health, medicine, pharmacology and industry. 2) Carbon a. Organic Chemistry is the study of carbon. So let’s review carbon. b. Atomic number = 6 c. Electron configuration = 1s22s22p2 d. Valence Electrons i. Definition: The electrons found in the outermost shell in the atom. 1. They are the electrons that can participate in bonding. 2. Note: Lone pair electrons are a subset of the valence electrons that do not participate in bonding. ii. 1s 2s 2p2 2 2 1. The electrons in the second shell (2s22p2) represent carbon’s valence electrons 2. 2 +2 =4 So carbon has four valence electrons iii. In order to complete its octet it needs to share four more electrons e. Octet Rule i. Definition: the sum of all bonding electrons and non-bonding electrons on a given atom in the 2nd row of the periodic table will never be greater than 8 ii. Exceptions to the Octet Rule: 1. Hydrogen and Lithium = 1 Valence Electron 2. Beryllium = 2 Valence Electrons 3. Elements in period 3 can occupy more than 8 valence electrons (e.g. Phosphorus and Sulfur) f. So if carbon has four electrons it may accommodate four more electrons i. How can it do so? It may gain four more bonds 1. One bond = 2 electrons 2. Carbon “takes on” one of those electrons from a given bond towards its octet © COPYRIGHT*2013*STUDYORGO.COM*LCC* Chapter Two: Drawing in Orgo 1) Learning organic chemistry is like learning a new language. With a new language  comes a new way of speaking and a new way of writing. In organic chemistry we communicate with lines and letters. 3) General rules of drawing in orgo using the “Line-Angle Formula” a. General Rule #1: i. Anytime there is a line drawn, the atom at each end is a carbon unless otherwise indicated. ii. The appropriate number of hydrogens are attached to it and implied even though they may not be drawn iii. For example, each of these three are equivalent depictions of the same compound: Looking at this Line-Angle Formula drawing we see a line. Each end of the line has a carbon. Since the carbons are connected by a single bond, each carbon has three hydrogens attached to it. b. General Rule #2: i. Each carbon molecule may accommodate four “things” attached to it via a single bond. If there is a double bond that counts as “two things” if there is a triple bond that counts as “three things” Well, there are three lines, right? Each positioned at an angle to one another to indicate that there is a new carbon at that joint Chapter Three: Molecular Orbitals, Hybridization and Geometry 1) Atomic orbitals a. Remember these subshells from general chemistry? i. s ii. p iii. d iv. etc. b. Each subshell has a certain number of atomic orbitals (represented by the lines below) i. s ___ one orbital ii. p ___ ___ ___ three orbitals iii. d ___ ___ ___ ___ ___ five orbitals c. Each atomic orbital can accommodate two electrons 2) Hybridization a. A hybrid or a mix of atomic orbitals b. An atom’s orbitals can interact with other atoms and overlap to form a given hybrid atomic orbital For example- here the sp hybrid atomic orbital is formed: 3) Molecular Orbitals a. Molecular orbital = overlap of two atomic orbitals from different atoms b.  There are two types of bonds formed in molecular orbitals: sigma bonds and pi bonds. c. sigma bond (σ)= overlap of hybridized orbitals along the line between nuclei i. single bonds are sigma bonds ii. double and triple bonds each have one sigma bond d. pi bond (π) = sideways overlap between two p orbitals i. double bonds have one pi bond ii. triple bonds have two pi bonds iii. there must be a sigma bond in order for a pi bond to occur e. Summary Chart Bond Sigma bonds Pi bonds Total Single 1 0 1 Double 1 1 2 Triple 1 2 3 4) Geometry a. An atom has a given hybridization depending on the number of bonds extending from it b. There is also an implicit geometric shape associated with the hybridization c. Furthermore, the bond angles formed are important d. Here is a chart that sums this up: © COPYRIGHT*2013*STUDYORGO.COM*LCC* Bond Hybridization Geometry Bond angle Picture Single sp3 Tetrahedral 109.5° Double sp2 Trigonal planar 120° Triple sp Linear 180° 5) Ways carbon can bond to others a. Option #1: Carbon may accommodate four single bonds  b. Option #2: Carbon may accommodate one double bond and two single bonds c. Option #3: Carbon may accommodate two double bonds d. Option #4: Carbon may accommodate one triple bond and one single bond © COPYRIGHT*2013*STUDYORGO.COM*LCC* Sign-Up for Full Access! For an interactive Exercise Set on Molecular Orbitals, Hybridization and Geometry, Sign Up and become a member of StudyOrgo.com. We are so confident in our program that we offer a guarantee like no other. We guarantee you will pass! While many students are happy with just passing this course, most of the students that we have feedback from, have excelled to be in the top of their class. For more information and to Sign-Up visit: https://www.studyorgo.com/signup.php © COPYRIGHT*2013*STUDYORGO.COM*LCC* Chapter Four: Lewis Structures, Formal Charge and Resonance Structures 1) What is a Lewis Structure? a. A way to draw out electrons and bonding by using dots 2) How do I draw a Lewis Structure? Let’s go step by step and demonstrate using CO2 as an example. a. Step 1: Determine the number of valence electrons an atom has to participate in bonding. i. Remember: Valence electrons are the electrons in the outermost shell of an atom. Some valence electrons participate in bonding to another atom. Others, known as lone pairs, do not. ii. The number of valence electrons that participate in bonding for popular atoms are as follows: C=4 N=3  O=2 F=1 H=1 ii. For example: In CO2 we have C (draw 4 dots) and O (draw 2 dots per atom) b. Step 2: Place a dot around that atom for each valence electron that participates in bonding i. For example: c. Step 3: Determine the lone pairs for a given atom: i. Remember: Lone pairs are a subset of the valence electrons that do not participate in bonding to another atom ii. Lone pairs for popular atoms are as follows: 1. C = 0 2. N = 1 pair = 2 electrons 3. O = 2 pairs = 4 electrons 4. F = 3 pairs = 6 electrons 5. H = 0 iii. For example, in CO2 we have C (no lone pairs) and O (two lone pairs per atom) d. Step 4: Place the lone pairs around the atom using a pair of dots to depict each lone pair. i. For example: e. Step 5: Wherever there is an atom bonding to another atom there are two dots between them, one from each atom. You may decide to convert this pair of electrons into a line to denote a bond. i. For example: 3) How do I figure out an atom’s formal charge? a. Step 1: Count the atom’s lone pair electrons © COPYRIGHT*2013*STUDYORGO.COM*LCC* b. Step 2: Count one from each pair of electrons that particular atom is using to bond to another atom c. Step 3: Add the number you get from Step 1 to Step 2 d. Step 4: The formal charge is whatever you need to do to the number you got from step 3 to get to the atom’s group number on the periodic table e. For example: Let’s use an O atom in CO2 as an example Add the lone pair electrons (4) to one from each pair of bonding electrons (2) = 6 Since oxygen is in group 6 in the periodic table the formal charge is 0 (zero). (You do not need to do anything to the number you get from step 3 to get to the atom’s group number on the periodic table) 4) What is resonance? a. A drawn structure with a double bond on its own does not completely represent the structure of a given molecule i. There can be more than one possible structure for the same  molecule! ii. The actual structure is the average of all of the resonance structures 5) Why resonance? a. Resonance spreads the charge over two atoms which makes the structure more stable 6) How do I figure out resonance problems? Follow these simple rules: a. Rule #1: Try moving around electrons. i. When moving electrons use an arrow to demonstrate where the electrons are going. ii. Electrons can be moved around in one of two ways: 1. Move double bond electrons 2. Move lone pair electrons b. Rule #2: The number of unpaired electrons must remain the same c. Rule #3: Figure out which of your drawings represent the major and minor structures i. Major resonance = the resonance contributors that are more stable as they have the least energy. Low energy structures satisfy as many of the following as possible: 1. There are as many octets as possible 2. There are as many bonds as possible 3. There are as few lone pairs as possible 4. Any negative charges are placed on the most electronegative atoms a. Most electronegative F > O > Cl > N > C least electronegative 5. There is the least separation of charge amongst the structures © COPYRIGHT*2013*STUDYORGO.COM*LCC* ii. Minor resonance = the resonance contributors that are less stable as they have the most energy. High energy structures do not satisfy as many of the above guidelines d. Example: NO3- i. In the following example NO3-is drawn out showing three different resonance structures. Please remember that while electrons are moving around no atoms are moving. ii. The arrows show the movement of the electrons to show how to arrive at the next structure moving from the left to the right of the screen. iii. Since all three structures satisfy the same guidelines to the same extent as outlined above, all three are equal contributors. However this is often not the case and will be seen in the next exercise set. Chapter Five: Basic Naming in Orgo- Naming Alkanes Each structure in organic chemistry has its own name Alkanes are one of the first structures to learn about when starting to study Organic Chemistry o Alkanes are molecules that are composed entirely by single bonds.  Follow these three simple steps to arrive at a name for a given molecule. o We will use this molecule as an example to demonstrate each step: Step #1: Find the longest chain of carbons in the molecule and number them starting with the carbon closest to a branch. Note: If there is a branch at the same point at either end, start numbering at the end closest to the largest branch. If the branches are of equal size at the same point at either end, start numbering at the end where the next branch is closer. Step #2: The number of carbons tells us the main stem of the structure’s name So in total that’s four carbons as part of the longest chain. This chart lists prefixes for structures based off the number of carbons in the longest chain. When naming alkanes, the three letter suffix “-ane” can be joined with the appropriate prefix to arrive at the main stem of the name. © COPYRIGHT*2013*STUDYORGO.COM*LCC* Number of Prefix Main stem of name carbons in if structure is an the longest alkane chain 1 Meth- Methane 2 Eth- Ethane 3 Prop- Propane  4 But- Butane 5 Pent- Pentane 6 Hex- Hexane 7 Hept- Heptane 8 Oct- Octane 9 Non- Nonane 10 Dec- Decane 11 Undec- Undecane 12 Dodec- Dodecane 13 Tridec- Tridecane 14 Tetradec- Tetradecane OK- so back to our example: In this case the prefix is But- Since it is made up of all single bonds, the structure is an alkane, and therefore the suffix is –ane Put together the prefix and the suffix and you have the main stem of the name. Prefix + suffix = main stem of the name o In this case But- + -ane = Butane Note: Other structure types will have different suffixes. For example, a structure with a double bond, is not an alkane, rather it is an alkene. Therefore the suffix would be “-ene.” A structure with a triple bond would have the suffix “-yne.” Bond Suffix Single -ane Double -ene Triple -yne Step #3: Is there anything else on that chain? If so—add it to the main stem of the name. © COPYRIGHT*2013*STUDYORGO.COM*LCC* Here there is a CH3 group. This is known as a methyl group. It is a type of alkyl group, which means a branch off a main molecule made up of carbons and hydrogen. o So you will need add that to the name. ▪ Check and see what carbon it is attached to—OK so it is attached to carbon #2. ▪ You need to add the numbered carbon, then a hyphen, then the substituent’s name. So the full name of this structure is: 2-methylbutane Some Important Details: 1) If there is more than one structure attached to the same carbon, list them in alphabetical order 2) If there is more than one of the exact same structure in the compound, then use the following table of prefixes to annotate the substituent name in the final overall name Number of the Prefix exact same group 2 di 3 tri 4 tetra 5 penta 3) To make naming easier, commit the following common alkyl groups and their names to memory: Chapter Six: Functional Groups © COPYRIGHT*2013*STUDYORGO.COM*LCC* Sign-Up for Full Access! For an interactive Exercise Set on Functional Groups, Sign Up and become a member of StudyOrgo.com. We are so confident in our program that we offer a guarantee like no other. We guarantee you will pass! While many students are happy with just passing this course, most of the students that we have feedback from, have excelled to be in the top of their class. 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