Unit 2: Atomic Structure Flashcards
define wavelength
- the distance between identical points on successive waves
- distance from peak to peak
what are the units for wavelength
- nanometers (nm)
- 1nm = 10^-9m
define frequency
- number of wavelengths that pass through a particular point in one second
- wavelengths per second
what are the units for frequency
- hertz (Hz)
- also denoted as s^-1
what is the order of the electromagnetic spectrum from low frequency/long wavelength to high frequency/short wavelength
- radio
- microwave
- infrared
- visible
- ultraviolet
- x-ray
- gamma rays
which electromagnetic rays are more dangerous to humans
- ultraviolet
- x-ray
- gamma rays
what is the order of visible colors from longer to shorter wavelenghts
ROYGBIV
what is the wavelength in nm of the visible color red
700 nm
what is the wavelength in nm of the visible color violet
400 nm
what is the equation including speed of light (c) wavelength (λ) and frequency (ν)
λν=c
what is the speed of light in m/s
2.9979 x 10^8 m/s
how are wavelength and frequency related
- inversely proportional
- as one increases, the other decreases
is the color of light caused by wavelength or amplitude
wavelength
is the brightness of light caused by wavelength or amplitude
amplitude
what is the value of Planck’s constant (h)
6.63E-34 J*s
what is the equation relating to energy, frequency, and wavelength
E=hv or E=hc/λ
what did Max Planck discover
energy from radiation emitted from hot objects is quantized
explain the word quantized
- very specific values that relate to something
- ex: potential energy on stairs is a very specific amount for each stair you’re on, you can’t be in between steps
- ex: energy of electrons on each electron ring, electrons can’t be in between rings
explain how Einstein discovered how to measure the amount of energy needed to eject an electron from a metal (photoelectric experiment)
- he would shine a light on the metal surface in an evacuated chamber
- he would increase the frequency of the light until the current indicator would spike which indicates that electrons have been ejected
- he discovered that different metals required different amounts of energy to eject electrons
explain binding energy
- amount of energy used to keep electrons orbiting the nucleus
- an equal amount of energy acting on the atom can eject the electron
write the equation for energy in terms of frequency and it terms binding and kinetic energy
E=hv=E(binding) + E(kinetic)
explain what happens if the energy acting on an electron is greater than the binding energy
- will create kinetic energy
- enough of the energy will be used to eject the electron and the rest will act as kinetic energy
what are the two ways light can behave
- particle/photon
- wave
what happens to energy as frequency increases
energy increases
what happens to energy as frequency decreases
energy decreases
what happens to energy as wavelength increases
energy decreases
what happens to energy as wavelength decreases
energy increases
how are wavelength and energy related
inversely proportional
how are frequency and energy related
directly proportional
what do we see when we look at a continuum source of light through a prism
- continuous spectrum
- all colors of the rainbow
what do we see when we look at a continuum source of light through a cloud of gas and then through a prism
- absorption spectrum
- see all colors except those absorbed by the gas
describe the absorption spectrum
- spectrum of visible light that is seen through a cloud of gas and a prism
- specific wavelengths (colors) are missing and have been absorbed by the gas
- produced when atoms absorb energy
describe the emission spectrum
- opposite of absorption spectrum
- the wavelengths that a gas will emit
- produced when atoms release energy
why is atomic emission/absorption spectroscopy useful
can help determine what elements are in something
explain why orbital levels are consider quantized
electrons can only occupy the specific orbitals and can’t be in between them
where are the lowest and highest energy levels of electron orbitals
- lowest energy: closest to nucleus
- highest energy: furthest from nucleus
what happens to the space between electron orbitals as you move further from the nucleus
space between orbitals gets smaller as energy levels increase
which direction do electrons move when the atom absorbs energy (absorption)
electrons move from low energy levels to high energy levels
which direction do electrons move when the atom releases energy (emission)
electrons move from high energy levels to low energy levels
define ground state
lowest possible energy configuration