CHEM 110 Misc. Vocab

Isosurfaces

"skins"

Monochromator

(such as a prism or a diffraction grating) used to separate the wavelengths of light, and a movable slit can be used to select the specific wavelengths to be measured in turn while exploring the full spectrum.

All orbitals with spherical symmetry are...

s-type orbitals: 1s, 2s, and 3s with n and ℓ defined (ℓ = 0).

a subscript 0

A convenient unit of length on the atomic scale called the Bohr radius; it has a numerical value of 5.29 × 10-11 m = 0.529 Å

Spectrophotometer

An instrument that can quantify the portion of light absorbed at all wavelengths of interest.

Anion

An ion with a net negative charge (excess of electrons)

1st Law of Thermodynamics

Energy cannot be created or destroyed (the law of the conservation of energy)

Anomalies in electron configurations are caused by:

subtle differences in subshell energies

Quantum

the amount of energy needed to move an electron from one energy level to another

The Effective Nuclear Charge

the attractive positive charge of nuclear protons acting on valence electrons

Quantization

the concept that energy can occur only in discrete, precise units called quanta

The sum of all probability densities for all volume units must equal...

1

Ion

Atoms that gain or lose electrons

Principal Quantum Number

Describes the energy of an electron and the most probable distance of the electron from the nucleus.

The collection of orbitals with the same value of n is called an...

Electron Shell

Valence Electrons

Electrons on the outermost energy level of an atom. Surround the outside of the core shells.

Molecular compounds

Molecules constructed with more than one type of atom

Pauli exclusion principle

No two electrons in an atom may occupy the same space and have all the same quantum numbers.

Arcs

Partial circles

Orbitals

Solving the Schrödinger equation for a hydrogen atom gives us a series of wavefunctions with their associated specific energies describing the ground-state and excited states of the atom. These solutions are called _________ in order to distinguish them from the deterministic orbits of Bohr's model.

Quanta

The bundle of electromagnetic energy that is absorbed or emitted by matter

Black-Body Radiation

The distribution of frequencies of radiation emitted by a heated body --- When solids are heated they emit radiation.

Coulomb's Law

The electrons do not fly away from the atom because they are attracted to the protons in the nucleus by an electrostatic force that is proportional to the magnitude of the charges on the interacting particles and inversely proportional to the square of the distance between them.

Core Electrons

The electrons in the inner shells of an atom; these electrons are not involved in forming bonds. They make up the core shells.

Photoelectric Effect

The emission of electrons from a material when light of certain frequencies shines on the surface of the material

Enthalpy

The heat exchanged with the surroundings under constant pressure

Valence

The number of bonds formed is called the ____________ of the atom.

Heisenberg uncertainty principle or indeterminacy principle

The position and the velocity of an object cannot both be measured exactly, at the same time, even in theory. The very concepts of exact position and exact velocity together, in fact, have no meaning in nature.

Ambient Pressure

The pressure in the area immediately surrounding the object.

Propagation

The spread of the action potential down an axon, caused by successive changes in electrical charge along the length of the axon's membrane.

Spectroscopy

The study of the interactions of light with matter.

A mole is...

a sample containing Avogadro's number of objects

Cation

an ion with a net positive charge (deficiency of electrons)

The magnetic quantum number (mℓ)

can have integral values between -ℓ and ℓ, including zero. This quantum number describes the spatial orientation of the orbital.

The principal quantum number (n)

can have positive integral values (n = 1, 2, 3...) as in Bohr's model. As n increases, the orbital becomes larger, and on average the electron spends more time farther away from the nucleus. Because of the diminished electrostatic attraction, the energy of the orbital increases with n and it does so in exactly the same manner as it did in Bohr's model

The angular momentum quantum number (ℓ)

can take on any integral value from 0 to (n-1). This quantum number defines the shape of the orbital. For historic reasons, specific values of ℓ have letter designations. For higher values of ℓ, the alphabetical order is followed with g for ℓ = 4 and so on.

degenerate

equal energy

The change in internal energy of a system results from the exchange of...

heat or work with the surroundings

The dumbbell-shaped orbitals are...

p-type orbitals, 2p and 3p (ℓ = 1) with nodes at the nucleus.

Nodes

regions where electrons are not allowed to be (can also appear in patterns)

Allotropes

two or more different molecular forms of the same element in the same physical state