Electromagnetic radiation
a form of energy that exhibits wavelike behavior as it travels through space
Electromagnetic spectrum
all the forms of electromagnetic radiation
Wavelength
the distance between corresponding points on adjacent waves
Frequency
the number of wave that pass a given point in a specific time (usually one second)
waves/second or hertz (Hz)
c=?v
c is the speed of light (m/s)
? is the wavelength of the electromagnetic wave (m)
v is the frequency of the electromagnetic wave (s?�)
? is inversely proportional to v (as one increase the other decreases)
Photoelectric effect
the emission of electrons from a metal when light shines on the metal (electromagnetic radiation is absorbed by matter only in whole numbers of photons)
Quantum
the minimum quantity of energy that can be lost of gained by an atom
E=hv
E is the energy of a quantum of radiation (joules)
v is the frequency of the radiation emitted (s?�)
h is Planck's constant
Planck's constant (formula)
h= 6.626 x 10?�? J?s
Planck's constant (theory)
introduced by German physicist Max Planck
Albert Einstein expanded on Planck's constant by introducing the idea that electromagnetic radiation has a dual wave-particale nature: it has wavelike properties and can be thought of as a stream of particles (eac
Photon
(definition and equation)
a particle of electromagnetic radiation having zero mass and carrying a quantum of energy. the energy of a particular photon depends on the frequency of radiation
E?photon=hv
ground state
the lowest energy state of an atom
excited state
a state in which and atom has a higher potential energy then it has a ground state
line-emission spectrum
four specific colors that you can see when a narrow beam of light shines through a prism and is separated in to the four specific colors of the visible light spectrum
continuous spectrum
the admission of a continuos range of frequencies of electromagnetic radiation
Bohr's model
(designed by Niels Bohr) a model of an atom where electrons can circle the nucleus only in allowed paths (orbits) and these electrons have a definite fixed energy
orbits
the allowed paths on which electrons can orbit the nucleus
emission
the process in which an electron falls to a lower energy level and emits a photon.
the photon's energy level is equal to the energy difference between the initial higher energy level and the final lower energy level.
absorption
the process of adding energy to an atom in order to move an electron from a lower energy level to a higher energy level
Diffraction
the bending of a wave as it passes by the edge of an object of through a small opening
Interference
it occurs when waves overlap, resulting in a reduction of energy in some areas and an increase of energy in others
Heisenberg uncertainty principle
(proposed by Werner Heisenberg) it states that it is impossible to determine simultaneously both the position and velocity of and electron or any other particle
Quantum Theory
this theory describes mathematically the wave properties of electrons and other very small particles
Orbital
a three-dimentional region around the nucleus that indicates the probable location of an electron
Quantum number
specify the properties of atomic orbitals and the properties of electrons in orbitals
principal quantum number
symbolized by n, it indicates the main energy level occupied by the electron. values of n are positive integers and as n increases, the electron's energy and it's average distance from the nucleus increases.
electron shell
a grouping of electrons surrounding the nucleus of an atom
electron sublevels
the layers of the electron shells that come before (are closer to the center) then the outer shell
electron outer shell
the valence electrons in this shell determine the chemical properties of that atom/element.
angular momentum quantum number
symbolized by l, indicates the shape of the orbital. values of l are zero and all positive integers less then and equal to n-1 (ex. n=2 then it can have two shapes corresponding to l=0 or l=1)
l=0 --- s orbital and it's spherical
l=1 --- p orbital and it
magnetic quantum number
symbolized by m, indicates the orientation of and orbital around the nucleus.
values of m are whole numbers including zero from -l to +l
spin quantum number
it indicated the two fundamental spin states of an electron in an orbital. only two possible values (+�, -�)
electron configuration
the arrangement of electrons in an atom which is unique to each element
ground-state electron configuration
the lowest energy arrangement of the electrons for each element
Aufbau principle
an electron occupies the lowest-energy orbital that can receive it
Pauli exclusion principle
no two electrons in the same atom can have the same set of four quantum numbers
Hund's rule
orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state
highest-occupied energy level
the electron-containing main energy level with the highest principal quantum number
inner-shell electrons
electrons that are not in the highest-occupied energy level
Octet
atoms prefer to have eight electron in their highest occupied level
Noble Gases
the Group 18 elements which have naturally have a full outer shell (eight electrons in their highest occupied level). Elements: helium, neon, argon, krypton, xenon, and radon
noble-gas configuration/notation
an outer main energy level occupied, in most cases, by eight electrons. It's a way of simplifying an element's electron configuration by comparing it to the closest noble gas that has a lower atomic value.