Ch 6

Front 1

wavelength (λ)

Back 1

The distance between identical points on successive waves

Front 2

frequency (ν)

Back 2

The number of times per second that one complete wavelength passes a given point

Front 3

Planck’s constant (h)

Back 3

The constant that relates the energy and frequency of a photon, E = hν. Its value is 6.662 X 10⁻³⁴J/s

Front 4

photoelectric effect

Back 4

The emission of electrons from a metal surface induced by light

Front 5

photons

Back 5

The smallest increment (a quantum) of radiant energy; a photon of light with frequency v has an enegy equal to hv

Front 6

spectrum

Back 6

The distribution among various wavelengths of the radiant energy emitted or absorbed by an object

Front 7

continuous spectrum

Back 7

A spectrum that contains radiation distributed over all wavelengths

Front 8

line spectrum

Back 8

A spectrum that contains radiation at only certain specific wavelengths

Front 9

ground state

Back 9

The lowest-energy, or most stable, state

Front 10

excited state

Back 10

A higher energy state than the ground state.

Front 11

matter waves

Back 11

The term used to describe the wave characteristics of a moving particle

Front 12

uncertainty principle

Back 12

A principle stating there is an inherent uncertainty in the precision with which we can simultaneously specify the position and momentum of a particle. This uncertainty is significant only for particles of extremely small mass, such as electrons

Front 13

wave function

Back 13

A mathematical description of an allowed energy state (an orbital) for an electron in the quantum mechanical model of the atom; it is usually symbolized by the Greek letter ψ

Front 14

probability density

Back 14

(ψ²) A value that represents the probability that an electron will be found at a given point in space. Also called electron density

Front 15

electron density

Back 15

The probability of finding an electron at any particular point in an atom; this probability is equal to ψ², the square of the wave function. Also called the probability density

Front 16

orbital

Back 16

An allowed energy state of an electron in
the quantum mechanical model of the atom; the
term orbital is also used to describe the spatial distribution
of the electron.An orbital is defined by the
values of three quantum numbers: n, l, and mₗ

Front 17

electron shell

Back 17

A collection of orbitals that have the same value of n. For example, the orbitals with n = 3 (the 3s, 3p, and 3d orbitals) comprise the third shell.

Front 18

subshell

Back 18

One or more orbitals with the same set of quantum numbers n and l. For example,we speak of the 2p subshell (n = 2, l = 1), which is composed of three orbitals (2pₓ, 2p(subscript)y, 2p(subscript)z)

Front 19

radial probability function

Back 19

The probability that the electron will be found at a certain distance from the nucleus

Front 20

node

Back 20

Points in an atom at which the electron density is zero. For example, the node in a 2s orbital is a spherical surface

Front 21

degenerate

Back 21

A situation in which two or more orbitals have the same energy

Front 22

spin magnetic quantum number (mₛ)

Back 22

A quantum number associated with the electron spin; it may have values of +1/2 or -1/2

Front 23

Pauli exclusion principle

Back 23

A rule stating that no two electrons in an atom may have the same four quantum numbers (n, l, mₗ, and mₛ, and ms ). As a reflection of this principle, there can be no more than two electrons in any one atomic orbital.

Front 24

electron configuration

Back 24

The arrangement of electrons in the orbitals of an atom or molecule

Front 25

Hund’s rule

Back 25

A rule stating that electrons occupy degenerate orbitals in such a way as to maximize the number of electrons with the same spin. In other words, each orbital has one electron placed in it before pairing of electrons in orbitals occurs.

Front 26

valence electrons

Back 26

The outermost electrons of an atom; those that occupy orbitals not occupied in the nearest noble-gas element of lower atomic number. The valence electrons are the ones the atom uses in bonding

Front 27

core electrons

Back 27

The electrons that are not in the outermost shell of an atom

Front 28

representative (main-group) element

Back 28

An element from within the s and p blocks of the periodic table

Front 29

transition elements

Back 29

(transition metals)Elements in which the d orbitals are partially occupied.

Front 30

lanthanide (rare earth) element

Back 30

Element in which the 4f subshell is only partially occupied.

Front 31

f-block metals

Back 31

Lanthanide and actinide elements in which the 4f or 5f orbitals are partially occupied.

Front 32

Back 32

light as a wave: c = speed of light (3.00 X 10⁸ m/s) λ = wavelength in meters, v = frequency in s⁻¹

Front 33

Back 33

light as a particle (photon): E = energy of photon in joules, h = Planck’s constant (6.626 X 10⁻³⁴ J-s) n = frequency in s⁻¹

Front 34

Back 34

matter as a wave: λ = wavelength in meters, h = Planck’s constant m = mass of object in kg, v = speed of object in m/s

Front 35

Back 35

Heisenberg’s uncertainty principle. The uncertainty in position Δx and momemtum Δmv of an object cannot be zero; the smallest value of their product is h/ 4π

Front 36

electronic structure

Back 36

The arrangement of electrons in an atom or molecule

Front 37

electromagnetic radiation

Back 37

(radiant energy)
A form of energy that has wave characteristics and that propagates through a vacuum at the characteristic speed of 3.00 X 10⁸ m/s

Front 38

∆E = −R(subscript H) ( 1/n²[subscript f] -1/n²[subscript i] )

Back 38

The energy absorbed or emitted from the process of electron promotion or demotion;

where R(sub H) is the Rydberg constant, 2.18 × 10 ⁻¹⁸ J, and ni and nf are the initial and final energy levels of the electron