Chemistry Chapter 4 Vocab

photoelectric effect

The emission of electrons from a metal when light shines on the metal

quantum

the minimum amount of energy that can be gained or lost by an atom

Photon

A particle of electromagnetic radiation with no mass that carries a quantum of energy

ground state

The lowest energy state of an atom

excited state

A state in which an atom has a higher energy than it has in its ground state

Heisenberg uncertainty principle

states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle

quantum theory

describes mathematically the wave properties of electrons and other very small particles

Orbital

A three-dimensional region around the nucleus that indicates the probable location of an electron

principal quantum number

symbolized by n, indicates the main energy level occupied by the electron

angular momentum quantum number

symbolized by l, indicates the shape of the orbital

magnetic quantum number

symbolized by m, indicates the orientation of an orbital around the nucleus

spin quantum number

The quantum number that has only two possible values, +1/2 and -1/2, which indicate the two fundamental spin states of an electron in an orbital

Aufbau Principle

states that each electron occupies the lowest energy orbital available

Pauli Exclusion Principle

states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins

Hund's Rule

states that electrons occupy empty orbitals with the same energy level before completely filling a partially-filled orbital up

noble gases

Elements in group 18 of the periodic table, are defined as being entirely unreactive

noble gas notation

An abbreviated electron configuration of an element in which filled inner shells are represented by the symbol of the preceding noble gas in brackets