Nuclear Change

radioactivity

process in which an unstable nucleus emits one or more particles of energy in form of electromagnetic radiation (radioactive decay)

beta particle

charged electron emitted during a certain type of radioactive decay

beta decay

radioactive decay in which charged electron turns into proton, often in unstable nuclei of large N/Z ratio

electron capture

the nucleus absorbs one of the atom’s electrons, changing proton into a neutron (mass # stays the same)

gamma rays

high energy photon emitted by a nucleus during fission and radioactive decay

positrons

antiparticle of electrons

alpha particle

helium nucleus (He-4)

annihlation of matter

any time a particle collides w/ its antiparticle, mass is converted into gamma rays

alpha decay

unstable nucleus w/ larger than 1 N/Z # decaying by losing alpha particles

nuclear fisson

splitting of the nucleus of a large atom into 2 or more fragments, producing additional neutrons and lots of energy

chain reaction

a reaction in which a change in a single molecule makes many molecules change, until a stable compound forms

critical mass

the minimum quantity of radioactive material needed to keep the chain reaction going

nuclear fusion

the combination of small nuclei to form a larger, more stable nucleus