Definitions of terms from chapter 1 of Solomons and Fryhle seventh edition
What are structural formulas?
Schematic representations of molecules to show their molecular geometry.
What are isomers?
Molecules with the same molecular formula but different molecular structures.
What are constitutional isomers?
Molecules with the same molecular formula but with different connectivity of atoms, e.g.
What is connectivity?
The connections of atoms to other atoms in a molecular structure.
What is electronegativity?
A measure of the ability of an atom to attract electrons. Electronegativity increases going up and to the right on the periodic table.
What are ionic bonds?
Bonds formed between atoms having a large difference in electronegativity, the more electronegative element "takes" the electron(s) from the less electronegative element. This typically occurs between a metal and a non-metal. The molecular orbitals are such that only one atom is contributing to the bonding orbital.
What are covalent bonds?
Covalent bonding occurs when two atoms have little difference in their electronegativities. This typically occurs between non-metallic atoms. Covalent bonds are formed by a sharing of electrons within molecular orbitals.
What are single bonds?
In organic chemistry single bonds refer to a covalent sigma bond.
What are double bonds?
In organic chemistry double bonds refer to a covalent sigma bond and a covalent pi bond between the same two atoms.
What are triple bonds?
In organic chemistry triple bonds refer to a covalent sigma bond and two covalent pi bonds between the same two atoms.
What are Lewis structures?
A representation of a molecule or ion showing the atomic symbol(s), bonding, and unshared electron pairs, e.g.
What is formal charge?
The positive or negative charge on an atom within a molecule.
What is the dash structural formula of ethanol?
What is the condensed structural formula of ethanol?
What is the bond line formula of ethanol?
What are stereoisomers?
Molecules that have the same connectivity but differ in their arrangement of atoms in space, e.g.
What are the precepts of resonance theory?
1) No single Lewis structure is the correct depiction of the molecule in question.
2) The actual molecule is shown by a hybrid of multiple structures.
What does resonance theory state?
Whenever a molecule, or ion, can be represented by two or more Lewis structures that differ only in the positions of the electrons then precepts of resonance theory must be applied.
What is wave function?
The wave function is a calculation that determines the particular energy of an electron.
What is electron probability density?
The square of the wave function yields a (x,y,z) probability of finding an electron in a particular region of space.
What is an orbital?
A region of space where the probability of finding an electron is large.
What is an atomic orbital?
A region of space about the nucleus of a single atom where the probability of finding an electron is large, e.g. the s orbital.
What are hybrid atomic orbitals?
Combinations of atomic orbitals that result in a lower energy ground state for atoms in molecules, e.g. sp3 hybridization.
What are molecular orbitals?
Orbitals that exist due to the overlap of atomic orbitals (of the same phase) from two atoms. Molecular orbital formation causes bonding and antibonding orbitals to form, the bonding are always at a lower energy level.
What are electron density surfaces?
A graphic illustration of a molecule that shows where electron density is greatest and the furthest extent of overall electron density.
What is an electrostatic potential map?
A graphic representation of charge distribution in a molecule or ion (red = negative / blue = positive).
What is the VESPR model?
A model used for predicting molecular geometry based on estimations of bonding and non-bonding electron pairs.
What is the aufbau principle?
Orbitals are filled with electrons so that those of the lowest energy are filled first.
What is the Pauli exclusion principle?
A maximum of two spin-paired electrons may be placed in any one orbital.
What does Hund's rule state?
When orbitals of the same energy are filled (e.g. the Px, Py, and Pz orbitals) one electron is added to each orbital before any are paired.