Question | Answer |
Atomic Number | The number of protons in an atoms nucleus. |
Constitutional Isomer | Compounds that have the same molecular formula but differ in the order in which atoms are connected |
Isotope | Atoms that have the same atomic number (same number of protons), but have different mass numbers (due to the fact that they have different number of neutrons)
ex. C^12 vs C^13 vs C^14 (which is radioactive) |
Atomic Orbital | Region where there is a high probability of finding an electron |
Degenerate Orbitals | Orbitals that have the same amount of energy |
Ground-State Electronic Configuration | The orbitals occupied by the atom''s electrons when they are all in the available orbitals with the lowest energy. |
Excited-State Electronic Configuration | When energy is applied and one or more electrons can jump into a higher energy orbital. |
Aufbau Principle | States that: an electron always goes into the available orbital with the lowest energy. |
Pauli Exclusion Principle | States that:
(a) no more than two electrons can occupy each atomic orbital
(b) the two electrons must be of opposite spin |
Mass Number | The sum of an atoms protons and neutrons. |
Atomic Weight | The average mass of an elements isotopes |
Atomic Mass Unit (amu) | Defined as 1/12 of the mass of C^12. |
Molecular Weight | The sum of the mass of all the atoms in a molecule. |
Hund's Rule | States that: where there are degenerate orbitals (two or more orbitals with the same energy) an electron will occupy an empty orbital before it will pair up with another electron. (Therefore electron repulsion is minimized) |
Core Electrons | Electrons in inner shells. |
Valence Electrons | Electrons in the outermost shell. |
Octet Rule | States that: an atom is most stable if its outer shell is either filled or contains eight electrons, and it has no electrons of higher energy. |
Electropositive Atoms | Elements that readily lose an electron and thereby become positively charged. |
Electronegative Atoms | Elements that readily acquire an electron and thereby become negatively charged. |
Bond | An attractive force between two ions or between two atoms. |
Ionic Bond | A bond that results from the electrostatic attraction between ions of opposite charge. |
Covalent Bond | A bond formed as a result of sharing electrons. |
Nonpolar Covalent Bond | A covalent bond between atoms that share electrons equally so that each electron spends as much time in the vicinity of one atom as in the other. |
Polar Covalent Bond | A covalent bond between atoms of different electronegativities so that electrons are not shared equally. |
Dipole | A molecule that has a negative end and a positive end. |
Lewis Structures | Chemical structures in which valence electrons are represented as dots. |
Lone-Pair Electrons | Valence electrons not used in bonding. |
Formal Charge | = number of valence electrons
- (number of lone-pair electrons + 1/2 number of bonding electrons) |
Free Radical | A species containing an atoms with a single unpaired electron. |
Heisenberg Uncertainty Principle | States that: both the precise location and teh momentum of an atomic particle cannot be simultaneously determined. |
Node | A region around an atom where the probability of finding an electron falls to zero. |
Molecular Orbitals | Orbitals that belong to the whole molecule rather than to a single atom. |
Sigma Bonding Molecular Orbital | The constructive combination of two s orbitals. |
Sigma Antibonding Molecular Orbital | The destructive combination of two s orbitals. |
Pi Bonding Molecular Orbital | Side to side overlap of two parallel in-phase p atomic orbitals. |
Pi Antibonding Molecular Orbital | Side to side overlap of two parallel out-of-phase p orbitals. |
Hybrid Orbitals (hybridization) | Mixed orbitals that result from combining atomic orbitals. |
How many Sigma bonds does a single bond have?
How many Pi bonds does a single bond have? | 1 Sigma bond;
0 Pi bonds |
How many Sigma bonds does a double bond have?
How many Pi bonds does a double bond have? | 1 Sigma bond;
1 Pi bond |
How many Sigma bonds does a triple bond have?
How many Pi bonds does a triple bond have? | 1 Sigma bond;
2 Pi bonds |
Nomenclature | The system of principles, procedures, and terms related to naming, which is the assigning of a word or phrase to a particular object or property. |
Common name | A non-systematic name |
When a hydrogen becomes replaced with an OH group the compound becomes a(n):
i.e. R-OH | Alcohol |
When a hydrogen becomes replaced with an NH2 group the compound becomes a(n):
i.e. R-NH2 | Amine |
When a hydrogen becomes replaced with a Halogen group the compound becomes a(n):
i.e. R-X | Alkyl halide |
When a hydrogen becomes replaced with an O-R group the compound becomes a(n):
i.e. R-O-R | Ether |
Primary Carbon | A carbon bonded to only one other carbon. |
Secondary Carbon | A carbon bonded to two other carbons. |
Tertiary Carbon | A carbon bonded to three other carbons. |
Parent Hydrocarbon | Longest continuous carbon chain |
Cycloalkanes | Alkanes with their carbon atoms arranged in a ring. |