Term	Page #*	Definition/Explanation
antibonding orbital	345	An orbital, if occupied, decreases the strength of the bond between two atoms.
band gap	361	A range of energy where no band energies exist.
bond order(b)	352	For a diatomic molecule it is defined as the number of antibonding orbitals subtracted from the number of bonding orbitals.
bonding molecular orbital	343	A molecular orbital that contributes to the strength of the bond two atoms.
Born-Oppenheimer approximation	334	An assumption that the nuclei are so much heavier than the electrons that the nuclei can be treated as stationary with the electrons moving around them.
core orbitals	347	The orbitals of the inner, closed shell.
covalent bond	333	A chemical bond formed when two atoms share a pair of electrons.
delocalized	360	Each electron pair helps to bind several or all of the atoms together.
diamagnetic	353	A substance pushed out of a magnetic field because of paired electron spins in molecular orbitals.
dopants	363	Foreign atoms implanted in a semiconductor that can either withdraw electrons or donate electrons.
electronegative	355	The property of an atom to draw electrons towards itself.
equilibrium bond length	334	The distance between nuclei where the molecular potential energy curve is lowest. This is where the bond energy is least and the bond is therefore more stable.
even parity	354	When a molecule has been tested by inversion and the signs are the same.
Fermi level	362	Only truly defined at t=0, the Fermi level is the highest occupied molecular orbital.
heteronuclear diatomic molecule	355	A diatomic molecule formed from atoms of two different atoms.
highest occupied molecular orbital	358	The highest occupied molecular orbital.
homonuclear diatomic molecules	347	Diatomic molecules formed from identical atoms.
hybrid orbitals	38	Mixtures of atomic orbitals on the same atom.
hybridization	338	The blending together of the orbitals of an excited atom (one in which promotion has occurred).
insulators	360	Semiconductors that have a very low electrical conductivity.
inversion	354	The process of choosing a point outside a molecular orbital and noting the sign there, then passing through the center of the molecule to the opposite side and comparing the signs. If the signs are identical, it has even parity; if the signs are different, it has odd parity.
ionic bond	333	A chemical bond formed by the transfer of electrons from one atom to another and the consequent attraction between the ions formed.
ionic-covalent resonance	341	When the resonance of a molecule involves both ionic and molecular structures.
LCAO-MO	343	The term used to designate the approximate molecular orbital formed through linear combination of atomic orbitals.
linear combination of atomic orbitals	343	The simple addition of the two atomic orbitals to form the general shape of the corresponding molecular orbital.
lowest unoccupied molecular orbital	358	The lowest unoccupied molecular orbital.
metallic conductor	360	A substance in which conductivity decreases as the temperature increases.
molecular orbital energy level diagram	345	A chart displaying the relative energies of the atomic orbitals and the corresponding bonding and antibonding orbitals that they form.
molecular orbital theory	342	A theory in which electrons do not belong to particular bonds but rather that they should be treated a s spreading throughout the molecule.
molecular orbitals	342	An orbital similar to an atomic orbital, but which spreads over the entire molecule.
molecular potential energy curve	334	A graph of how the bond energy varies with internuclear distance.
nodal plane	344	A plane where the value of the wavefunction passes through zero.
nonpolar bond	357	A covalent bond in which the electrons are shared equally between the two atoms.
n-type semiconductor	363	A semiconductor where the dopants have a negative (hence the n) charge relative to the rest of the semiconductor.
odd parity	355	When a molecule has been tested by inversion and the signs are different.
overlap integral	349	evaluated over all space to determine the extent to which two orbitals overlap.
p band	361	The band formed by the overlap of p orbitals.
paramagnetic	353	A substance drawn into a magnetic field because of unpaired electron spins in molecular orbitals.
parity	354	A molecule's symmetric property when tested under the process of inversion.
partial negative charge	356	When the electron pair in a bond is pulled closer to one atom, resulting in a net negative charge, denoted -.
bond	336, 348	A bond formed by the side-by-side pairing of electrons in p-orbitals
orbital	348	A molecular orbital that resembles a p orbital when viewed along the internuclear axis. More precisely, it is so called because an electron that occupies a orbital has one unit of orbital angular momentum around the internuclear axis, just as a p electron has one unit of orbital angular momentum around the nucleus.
polar bond	355	A covalent bond in which the electrons are not shared evenly.
polar covalent bond	357	A covalent bond in which the electrons are not shared equally between the two atoms, represented by the wavefunction
promotion	338	The excitation of an electron to an orbital of higher energy.
p-type semiconductor	363	A semiconductor where the dopants have a positive (hence the p) charge relative to the rest of the semiconductor.
resonance	341	The superposition of different electron distributions in the same nuclear framework.
resonance hybrid	341	The hybrid formed by the superposition of the different resonance structures.
resonance stabilization	342	A resonance structure has a lower energy relative to the original structures because of the improvement of the wavefunction caused by hybridization.
s band	361	The band formed by the overlap of s orbitals.
semiconductor	360	A substance in which conductivity increases as the temperature increases.
bond	335, 346	A valence bond wavefunction with cylindrical symmetry around the internuclear axis.
electron	343	An electron that occupies an orbital.
orbital	343	A molecular orbital that resembles a s orbital when viewed along the internuclear axis. More precisely, it is so called because an electron that occupies a orbital has zero orbital angular momentum around the internuclear axis, just as a s electron has zero orbital angular momentum around the nucleus.
sp hybridized	339	A hybrid orbital built from one s orbital and one p orbitals. Two p orbital remains unhybridized in this configuration.
sp2 hybrid orbital	339	A hybrid orbital built from one s orbital and two p orbitals. One p orbital remains unhybridized in this configuration.
sp3 hybrid orbital	339	A hybrid orbital built from one s orbital and three p orbitals.
superconductors	360	Substances that conduct electricity without resistance.
superimpose	335	Add together two or more items, generally graphs/plots.
trial wavefunction	341	An arbitrary wavefunction used in the variation theorem.
valence bond theory	335	A theory in which a bond is formed when an electron in one atomic orbital pairs its spin with that of an electron supplied by another atomic orbital.
valence orbitals	347	The orbitals of the valence shell.
valence theory	333	The theory of the origin of the numbers, strengths, and three-dimensional arrangements of chemical bonds between atoms.
valence-shell electron pair repulsion	334	A simple model of molecular shape based upon the repulsion between electron pairs.
variation theorem	341	If an arbitrary wavefunction is used to calculate the energy, then the value calculated is never less than the true energy.
virtual orbitals	347	The orbitals of an atom that are unoccupied in the ground state.

This page was made by Erik Epp.