The three rules to forming the lewis dot structure:
1. find the total number of valence electrons for all atoms in the molecule.
2. Use one pair of electrons to form one bond between each atom.
3. Arrange the remaining electrons around the atoms to satisfy the duet rule for hydrogen and the octet rule for other atoms.
The electrons on the outer most level of an atom. It also let u know how many bonds an atom can make.
total # of valence electrons - # of bonds - # of lone pair electrons =
This indicates the number of pairs of hydrogens a compound requires in order to become a saturated alkane.
Index of hydrogen deficiency
formula for index of hydrogen deficiency
Carbon-Carbon single bond or methane
Carbon-Carbon double bond
carbon-carbon triple bond
Name the prefix for the 1-10 carbons
meth, eth, prop, but, pent, hex, hept, oct, non, dec
This forms when the bonding pair of electrons are localized directly between two bonding atoms. Any single bond, double bond or triple contain one of this
Double bonds are made by adding one of these bonds to a sigma bond.
Triple bonds are made by adding two of these to a sigma bond.
pi bonds (more reactive than sigma bond)
Name the hybridization, bond angles and shape for: 2 bonds, 3 bonds, 4 bonds, 5 bonds, 6 bonds
sp 180o, linear
sp2 120o, trigonal planar
sp3, 109.5, tetrahedral
sp3d, 90 & 120, trigonal-bipyramidal
sp3d2, 90, octahedral
Molecules containing delocalized electrons can be represented by a combination of two or more lewis structures called::
This occurs when the center of positive charge on a molecule or bond does not coincide withe the center of negative charge
This type of dipole moment causes the polar molecule or ion to create an electric field, which pushes the electrons and nuclei in opposite directions, separating the centers of positive and negative charge.
this dipole moment arise because the electrons in a bond move about the orbital and at any given moment may not be distributed exactly between the two bonding atoms even when the atoms are identical
This attraction between separate molecules occur solely due to dipole moments
This bond is the strongest type of dipole-dipole interaction. It is responsible for the high boiling point of water
H-O-H ---- O=C-C
__________ is the weakest dipole-dipole force. It is between two instantaneous dipoles.
It is responsible for the phase changes for non-polar molecules.
EX: H-H --- H-H
London Dispersion Forces
These isomers are not true isomers, they are different spatial orientations of the same molecule.
conformational isomers or conformers
This isomers are the simplest form of isomers. They have the same molecular formula but different bond to bond connectivity.
These molecules differ in their reflections
Any carbon is ____________ when it is bonded to four different substituents.
In chemistry, the "handedness" of a carbon is called
The only way to physically describe the orientation of atoms about a chiral center such as a chiral carbon.
There are two different configurations: R (right) or S (left)
Two molecules have the same ___________ about a carbon if they differ by only one substituent and the other substituents are oriented identically about the carbon.
The direction and the degree to which a compound rotates plane-polarized light is given by its ____________.
A ___________ screens out photons with all but orientation of electric field
The resulting light from the polarimeter consists of photons with their electric fields oriented in the same direction. This light is called _______
These stereoisomers have the same molecular formula, have the same bond-to-bond connectivity, are mirror images of each other, but are not the same molecule.
Two molecules with the same molecular formula and the same bond to bond connectivity that are not the same compound are called ______.
There are two types: enantiomers and diastereomers
When enantiomers are mixed together in equal concentrations, the resulting mixture is called ___________
a racemic mixture
For these stereoisomers, they have the same chemical and physical characteristics except for two cases: 1. reactions with other chiral compounds; 2. reactions with polarized light.
These stereoisomers have the same molecular formula, have the same bond to bond connectivity, are not mirror images, and are not the same compound.
These special type of diastereomers exist due to hindered rotation about a bond. Rotation may be hindered due to a ring structure or a double or triple bond.
Molecules with same side substituents are called __________
Have a dipole moment
have a higher boiling point b/c have stronger intermolecular forces
have lower melting point b/c don't form crystals
Molecules with opposite-side substituents are called ___________
Do not have a dipole moment
The substituent groups in the cis position may crowd each other; this condition is known ___________
Two chiral centers in a single molecule may offset each other creating an optically inactive molecule.
They have a plane of symmetry thru their centers which divides them into two halves that are mirror images to each other
Such a compound is known as a
Diastereomers that differ at only one chiral carbon are called __________