Electromagnetic energy and the Bohr model

Electromagnetic radiation can be imagined as...

a self-propagating transvers oscillating wave of electric and magnetic fields

Amplitude

the height of the wave maximum from the center

Wavelength

the distance between successive wave peaks

λ

lambda (wavelength)

Frequency

the number of waves passing a given point per unit of time

𝛎

nu (frequency)

constructive interference

perfectly aligned waves that combine to create a wave of larger amplitude

Destructive interference

off set waves that combine to create a wave of smaller amplitude

Standing waves

waves constrained within some region of space

one dimensional standing wave

both ends are fixed, only waves with an integer number of half wavelengths can form

wave theory

the theory that light is transmitted as waves

What can wave theory not explain?

blackbody radiation and the ultraviolet catastrophe

blackbody radiation

emission of light from hot objects

ultraviolet catastrophe

the failed prediction of classical physics that the energy radiated by a blackbody at extremely short wavelengths is extremely large and that the total energy radiated is infinite

quantum

the smallest amount of energy that can be emitted or absorbed as electromagnetic radiation (plural: quanta)

Quantization

the concept that energy can occur (released or absorbed )only in discrete units called quanta

Plank's constant

a number used to calculate the radiant energy (E) absorbed or emitted by a body based on the frequency of radiation

Photoelectric effect

The emission of electrons from a material when light of certain frequencies is absorbed by the surface of the material

Light can have ____ like properties

particle

Photon

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

Line spectra

pattern of lines produced by light emitted by excited atoms of an element

monochromatic

radiation composed of a single wavelength

continuous radiation

Electromagnetic radiation with intensity that varies smoothly over a wide range of wavelengths.

Continuous spectrums occur when...

radiation from a light source such as a light bulb is separated into its different wavelength components

Rydberg Equation

used to calculate the wavelengths of all the spectral lines of hydrogen

Three postulates of the Bohr Model

-only orbits of specific radii are permitted for electrons in an atom

-an electron in a permitted orbit has a specific energy

-energy is only emitted or absorbed by an electron as it moves from one allowed energy state to another

in the bohr model, energy is gained or lost as a...

photon

ground state

The lowest energy state of an atom

excited state

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

Photoemission occurs...

as an electron relaxes from a higher energy state to a lower one

light emitted from excited state atoms is...

quantized

when a photon is absorbed...

the electron moves to a higher energy level

when a photon is emitted

the electron moves to a lower energy level