
the arrangement of electrons in an atom or molecule 

electromagnetic radiation 

a form of energy that has awave characteristics and that propagates through a vacuum at the characteristic speed of 3.00*10^8 m/s 


the distance between identical points on successive waves 


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


the smallest increment of radiant energy that may be absorbed or emitted the magnitude of radiant energy is hv 


the constant that relates the energy and frequency of a photon E = hv; equals 6.626*10^34 Js 


the emissions of electrons from a metal surface induced by light 


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


a spectrum that contains radiation distributed over all wavelengths 


a spectrum that contains radiation at only certain specific wavelengths 


the lowest energy, or most stable, state 


a higher energy state than the ground state 


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


the product of the mass and velocity of an object 


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 


a mathematical description of an allowed energy state (an orbital) 


a value the represents the probability that an electron will be found at a given point in space 


the probability of finding tan electron at any particular point in an atom; this probability is equal to the square of the wave function 


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 defind the the values of three quantum numbers: n, l, and ml 


a collection of orbitals that have the same value of n 


one or more orbitals with the same set of quantum numbers n and l 

radial probability function 

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


points in an atom at which the electron density is zero; for example the node in a 2s orbital is spherical surface 


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


a property of the electron that makes it behave as though it were a tiny magnet; the electron behaves as if it were spinning on its axis; electron spin is quantized 

spin magnetic quantum number 

a quantum number associated with the electron spin 

Pauli exclusion principle 

a rule stating that no two electrons in an atom may have the same four quantum numbers; as a reflection of this principle, there can be no more than two electrons in any one atomic orbital 


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


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 


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


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


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


elements in the s and p blocks of the periodic table 


elements in which the d orbitals are partially occupied 

lanthanide (rare earth) elements 

element in which the 4f subshell is only partially occupied 


element in which the 5f orbitals are only partially occupied 


lanthanide and actinide elements in which the 4f and 5f orbitals are partially occupied 
