an area of an orbital having zero electron probability

Back

diffraction

Front

the scattering of light from a regular array of points or lines, producing constructive and destructive interference

Back

quantization

Front

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

Back

angular momentum quantum number

Front

(l) distinguishes orbitals of given n having different shapes; can have any integer value from zero to n-1

Back

valence electrons

Front

the electrons in the outermost principal quantum level of an atom

Back

quantum mechanical model

Front

the modern description, primarily mathematical, of the behaviour of electrons in atoms

Back

core electrons

Front

an inner electron in an atim

Back

standing wave

Front

a stationary wave as on a string of a musical instrument; in the wave mechanical model, the electron in the hydrogen atom is considered to be a standing wave

Back

probability distribution

Front

the square of the wave function indicating the probability of finding an electron at a particular point in space

Back

nodal surface

Front

node

Back

Planck's constant

Front

the constant relating the change in energy for a system to the frequency of the electromagnetic radiation absorbed or emitted

Back

wavelength

Front

the distance between two consecutive peaks or troughs in a wave

Back

orbital

Front

a specific wave function for an electron in an atom. The square of this function gives the probability distribution for the electron

Back

diffraction pattern

Front

bright spots and dark areas on a photographic plate

Back

Pauli exclusion principle

Front

in a given atom, no two electrons can have the same set of four quantum numbers

Back

line spectrum

Front

a spectrum showing only certain discrete wavelengths

Back

electron spin quantum number

Front

a quantum number representing one of the two possible values for the electron spin, either +1/2 or -1/2

Back

Heisenberg uncertainty principle

Front

a principle stating that there is a fundamental limitation to how precisely both the position and momentum of a particle can be known at a given time

Back

Aufbau principle

Front

electrons enter orbitals of lowest energy first

Back

dual nature of light

Front

the statement that light exhibits both wave and particulate properties

Back

subshell

Front

a set of orbitals with a given azimuthal quantum number (l). (7.6)

Back

ground state

Front

the lowest possible energy state of an atom or molecule

Back

quantum model

Front

the electron in a hydrogen atom moves around the nucleus only in certain allowed orbits

Back

electromagnetic radiation

Front

radiant energy that exhibits wavelike behaviour and travels through space at the speed of light in a vacuum

Back

E = mc2

Front

Einstein's equation proposing that energy has mass

Back

degenerate orbitals

Front

a group of orbitals with the same energy

Back

quantum numbers

Front

numbers which describe various properties of the orbital

Back

continuous spectrum

Front

a spectrum that exhibits all the wavelengths of visible light

Back

principal quantum number

Front

(n) the quantum number relating to the size and energy of an orbital; it can have any positive integer value

Back

magnetic quantum number

Front

m, the quantum number relating to the orientation of an orbital in space relative to the other orbitals with the same l quantum number. It can have integral values between l and - l , including zero. (7.6)

Back

transition metals

Front

several series of elements in which inner orbitals (d or f) are being filled

Back

frequency

Front

the number of waves (cycles) per second that pass a given point in space

Back

Hund's rule

Front

when electrons occupy orbitals of equal energy, one electron enters each orbital until all orbitals contain one electron with their spins parallel

Back

polyelectronic atoms

Front

an atom with more than one electron

Back

photon

Front

a quantum of electromagnetic radiation

Back

wave function

Front

a function of the coordinates of an electron's position in three-dimensional space that describes the properties of the electron