Chemistry 2

• Constitutional isomers are isomers with the same molecular formula but a different structural formula
• Stereoisomers have the same atoms connected by bonds, but differ in their spatial arrangement
• Enantiomers are stereoisomers that are non-superimposable mirror images of one another.
• Diastereomers are stereoisomers that are not enantiomers
• Diastereomers are stereoisomers that are not enantiomers.
• Cis-trans isomerism occurs when two groups on opposite sides of a double bond can be rotated to occupy positions on the other side of the double bond.
• Cis-trans isomerism occurs when there is a double bond between two carbon atoms
• The cis form has both substituents on the same side of the double bond while trans forms have them on opposite sides
• In cis-trans isomerism, the molecules can be superimposed if they are identical except for the positioning of the groups around the double bond
• The octet rule states that atoms can only have eight electrons in their outer shell
•  Covalent bonds have an electronegativity of 1.5
• Dipoles have an electronegativity of 1.5 and a polarity of 1
• A polar compound will dissolve in water because it attracts H+ ions from the water
• Ionic compounds have an electronegativity of 3 and a polarity of 4
• Nonpolar substances do not dissolve in water as they cannot interact with the hydrogen bonded structure of water
• Nonpolar covalent bonds have an electronegativity of 0 to 0.20
• Polar covalent bonds have an electronegativity of 0.20 to 1.90
• Friedrich Wohler converted ammonium cyanate to urea
• Carbon is tetravalent
• Halogens are monovalent
• To build isomers the atoms with the highest valency are connected first
• A covalent bond is when two atoms share electrons
• Valence electrons are defined by their group on the table
• The number of bonds an atom can form depends on its valency
• Covalent compounds have lower melting points, higher solubility in non-polar solvents, do not conduct electricity in solid or liquid states
• Always pair unpaired electrons to form at octet
• If there aren't enough pairs to make an octet then it will be polar
• Formal charge depends on if there are enough or too many valence electrons
• Triple bonds are linear
• Each carbon has enough hydrogen atoms to have exactly four bonds
• Orbitals define shape of electron cloud
• P orbitals have positive negative and a node
• P orbitals phases shouldn't be confused with electrical charge
• 2s has one orbital and is farthest away from nucleus, therefore has higher energy
• Orbitals with the same energy level are called degenerate orbitals
• The aufbau principle is the lowest energy orbital is filled first
• Pauli exclusion principle is an orbital occupies two electrons but must have opposite spin states
• Hunds rule is that one electron is placed in each degenerate orbital first, before electrons are paired up
• Covalent bonds happen when orbitals overlap
• Valence bond theory is the sharing of electron density between two atoms