The Electron Flashcards
Thermionic Emission
Giving off of electrons from the surface of a hot metal
Electronvolt
Amount of energy gained or lost by an electron when it moves through a potential difference of one volt
Photoelectric Effect
The emission of electrons from the surface of a metal by electromagnetic radiation of a suitable frequency
Threshold Frequency
For a given metal the frequency below which photoemission will not occur is called the threshold frequency. Light above the threshold frequency will cause photoemission
Work Function
(Of a metal) minimum energy needed to remove the loosest electron from the surface of that metal
Photon
Packet of electromagnetic energy
X-Rays
High frequency electromagnetic radiation produced when high speed electrons in a cathode ray tube strike a metal target that has a high melting point
Emission Spectrum
When light from a luminous source undergoes dispersion the resulting pattern is called an emission spectrum
Energy Level
The fixed amount of energy an electron in an atom may have
Atomic Number
Number of protons in the nucleus of an atom
Mass Number
The number of protons and neutrons in the nucleus of an atom
Isotopes
Atoms on an element that have the same number of protons but different number of nuetrons
Radioactivity
Spontaneous breaking up of the nuclei of certain atoms accompanied by the emission of one or more types of radiation
Alpha
Helium nuclei
Beta
Electrons
Gamma
Electromagnetic radiation
Activity
(Radioactive substance) the number of nuclei of that substance decaying per second
Law of Radioactive Decay
The number of nuclei decaying per second is directly proportional to the number of nuclei undecayed
Half-Life
(Radioactive isotope) is the time taken for half of the undecayed atoms to undergo decay
Mole
The amount of the substance the contains 6.02 x 1023 particles
