wave, particle
light is made of
radiation
the rays and particles (alpha and beta) that are emitted by radioactive material
visible light, x rays, microwaves, tv/radio waves
Examples of electromagnetic radiation
wavelength, frequency, and amplitude
characteristics of waves
wavelength symbol
λ
frequency symbol
V
wavelength
the shortest distance between equal points on a wave
frequency
the number of waves that passes a given point per second
amplitude
Height of a wave from the origin to a crest
Speed of light
(3.00 x 10^8 m/s) c=λV (wavelength x frequency)
Waves models don't explain
why heated objects emit only certain frequencies of light at a given temp and why some metals emit electrons when light of a specific frequency shines on them
quantum
the minimum amount of energy that can be gained or lost by an atom
quantum concept
Matter can gain or lose energy only in small specific amounts called quanta
photoelectric effect
The emission of electrons from a metal when light shines on the metal
photon
a massless particle that carries a quantum of energy
Planck's constant
6.626 x 10^-34 Js
Formula for the energy of a photon
E=hv
atomic emission spectrum
the set of frequencies of the electromagnetic waves emitted by atoms of the element
increases
When the wavelength decreases the frequency ____
ground state
The lowest energy state of an atom
Bohr's contribution
Electrons moved in orbits (incorrect), the number assigned to each orbit of an electron is a quantum number
Bohr lacked
his model explained hydrogen's spectral lines but not any other element, although not 100% sure - evidence shows electrons do not move around nucleus in circular orbits
de Broglie equation
λ = h/mv, predicts that all moving particles have wave characteristics
The Heisenberg uncertainty principle
it is impossible to know exactly both the velocity and the position of a particle at the same time, the only quantity that can be known is the probability for an electron to occupy a certain region around the nucleus
4
the quantum mechanical model assigns ____ quantum numbers to atomic orbitals
principal quantum number
symbolized by n, indicates the main energy level occupied by the electron, as n increases the orbital becomes larger
1
an atoms lowest principal energy level is assigned a principal quantum number of ___
energy sublevels
principal energy levels contain
Aufbau Principle
An electron occupies the lowest-energy orbital that can receive it
Pauli Exclusion Principle
two electrons occupying the same orbital must have opposite spins
Hund's rule
single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals
valence electrons
Electrons on the outermost energy level of an atom which are added up
Hund's Rule
example of Whose Rule/principle
Aufbau Principle
example of whose rule/principle
Pauli Exclusion Principle
examples of whose rule/principle