Ch. 9: Atomic and Nuclear Phenomena Flashcards
what phenomenon occurs due to the photoelectric effect
when light of sufficiently high frequency hits a metal in a vacuum the metal atoms emit electrons
an “all or nothing response”
what is the threshold frequency (fT)
the minimum frequency of light that causes ejection of electrons
depends on the type of metal
what is the equation for energy of a photon
E = hf
where h is Planck’s constant (6.626 E-34 Js) and f is the frequency of the light
equation for maximum kinetic energy of an ejected electron
Kmax = hf - W
where W is the work function of the metal
what is the work function of a metal
minimum energy required to eject an electron from it, similar to activation energy
what is the equation for the work function
W = hfT
where fT is the threshold frequency
what occurs during infrared spectroscopy
bonds in a chemical structure absorb different wavelengths of light
what occurs during UV-vis spectroscopy
evaluates how bonds in a chemical structure absorb different wavelengths of light and graphs the absorption across the entire spectrum
what occurs when a fluorescent substance is excited with UV radiation
electrons are excited to high energy states by UV radiation then fall back at 2+ steps, emitting frequencies much lower than absorbed, causing the substance will glow
what is the mass defect of a nucleus
phenomenon in which the mass of a nucleus is actually slightly less than the protons and neutrons that comprise it due to the mass that has been converted to energy
what is binding energy
the energy given off when neutrons and protons bind together and create a lower energy level
what occurs during nuclear reactions
nuclei of atoms are split or combined
what occurs during fusion reactions
small nuclei combine to form a larger nucleus
what occurs during fission reactions
a larger nucleus is split into smaller nuclei
what occurs during radioactive decay
certain nuclei spontaneously decay and emit specific particles
