Chem 210 Exam 1 questions with 100% correct answers.

sp Hybridization 2 SP + 2 π orbital Linear geometry at carbon sp² Hybridization 3 SP + 1 π orbital Trigonal planar geometry at carbon sp³ Hybridization 4 SP orbitals Tetrahedral geometry Antibonding MOs Destructive interference waves created by high energy electrons in MO models (Node is always present in antibonds) Bonding MOs Constructive interference waves created by lower energy electrons in MO models (No nodes, but beware of node-like low-probability regions) HOMO Highest Occupied Molecular Orbital -Holds highest energy electrons -NUCLEOPHILIC LUMO Lowest Unoccupied Molecular Orbital -Lowest energy empty orbital -ELECTROPHILIC Generic Ordering of MOs (by energy) σ* - Almost never occupied in ground state π* - Rarely occupied in ground state n - Non-bonding (LONE PAIRS) π - Always occupied in compounds w/ multiple bonds σ - At least 1 occupied in all molecules Nonpolar Covalent Bond Bond in which the electronegativity difference between bonded atoms is LESS THAN 0.5 Ex: C=C Polar Covalent Bond Bond in which the electronegativity difference between bonded atoms is BETWEEN 0.5 and 2.0 Ex: C=O Ionic Bond Bond in which the electronegativity difference between bonded atoms is MORE THAN 2.0 Ex: ONa Aliphatic Hydrocarbons Hydrocarbons which do not contain an aromatic ring Aromatic Hydrocarbons Hydrocarbons which do contain an aromatic ring (Benzene) Alkane Hydrocarbons which are saturated (all single bonds) -IUPAC Suffix = "___ane" -Formula = C(n)H(₂n+₂) Alkene Hydrocarbons which are unsaturated by one or more double bond -IUPAC Suffix = "___ene" -Formula = C(n)H(₂n) Alkyne Hydrocarbons which are unsaturated by one or more triple bond -IUPAC Suffix = "___yne" -Formula = C(n)H(₂n-₂) Eclipsed Conformation Atoms from one side of a molecule eclipse (are in alignment with) atoms from another side of a molecule -HIGHER ENERGY THAN STAGGERED CONFORMATION Staggered Conformation Atoms from one side of a molecule are out of alignment with atoms from another side of a molecule -LOWER ENERGY THAN ECLIPSED CONFORMATION Anti Conformation In a Newman Projection, component X is 180° from component Y. Ex: Methyl ends on butane at 180° from one another. Gauche Conformation In a Newman Projection, component X is 60° from component Y. Ex: Methyl ends on butane at 60° from one another. Axial Bonds Bonds in cyclohexane that are NOT parallel to C-C bonds in the ring. Equatorial Bonds Bonds in cyclohexane that sit parallel to C-C bonds within the ring. IUPAC Nomenclature (# Carbons) 1=meth, 2=eth, 3=prop, 4=but, 5=pent, 6=hex, 7=hept, 8=oct, 9=non, 10=dec, 11=undec, 12=dodec Substituent A group that is connected to a parent chain. *IUPAC RULE: Always choose parent chain with the MOST number of substituents! Cycloalkane Carbon ring connected by all single (σ) bonds. -IUPAC Name = "cyclo___ane" -Formula = C(n)H(₂n) IUPAC Prefixes for Multiple Substituents 2=di, 3=tri, 4=tetra, 5=penta IUPAC First Point of Difference Rule When deciding how to number substituents while naming molecules; If there is a tie for the first locant, use the second and so on until one finds the lowest number. Ex: 2,2,6,6,7-pentamethyloctane vs 2,3,3,7,7-pentamethyloctane 2,2,6,6,7-pentamethyloctane is the correct name, because 2,2 is lower than 2,3 IUPAC Alphabet Rule If the IUPAC First Point of Difference Rule makes no difference for two unique substituents, then one must pick the substituent that comes first in alphabetical order to possess the lowest locant. IUPAC Locant A number given to denote the location of a substituent on a parent chain. Ex: In 2-methylhexane, the methyl group is bonded to the second carbon in the hexane chain. Cycloalkanes as Substituents (Cycloalkyls) If the parent chain in a molecule contains more carbon atoms than a cycloalkane it is attached to, then the cycloalkane becomes a cycloalkyl group. -IUPAC Name = "cyclo___yl" -Ex: 4-cyclopropylheptane Primary Carbon A carbon connected to 1 other carbon. Secondary Carbon A carbon connected to 2 other carbons. Tertiary Carbon A carbon connected to 3 other carbons. Quaternary Carbon A carbon connected to 4 other carbons. Constitutional Isomers Two or more molecules that have: -SAME molecular formula -DIFFERENT bond connectivity Ex: hexane vs. 2-methlypentane Stereoisomers Two or more molecules that have: -SAME molecular formula -SAME bond connectivity -DIFFERENT different spatial arrangements of atoms/groups Ex: cis-1,2-dichloroethene vs. trans-1,2-dichloroethene