Big Idea 1: Nuclear chemistry – Flashcards

property of matter in which unstable nucleus spontaneously emits small particles to attain stability (radioactive decay)

emit subatomic particles - electron (beta particle) - neutron - helium nucleus (alpha particle) - positron

the nuclear mass and nuclear charge of the atom changes one isotope converted to another with a different identity -energy released in form of x-rays/gamma rays

collide less, usually do not penetrate skin

emitted in nuclear reactions, very penetrating -easily pass through because of zero charge, significant damage because of mass

travel few cm before colliding with air > lose KE > gain electrons > ordinary helium

positive equivalents to beta particles/electrons - unable to penetrate matter

proton + electron > neutron decreasing atomic number by 1

produced when some radioactive decay event occur -nucleus has excess energy > energy lost as gamma ray -no charge or mass, penetrate easily

highly penetrating electromagnetic radiation -penetrate body unless blocked by dense structure like bones

polonium Z = 84 to uranium Z = 92 and potassium 40, vanadium 50, lanthanum 138

92-118 artificial and radioactive

radon-222: potential environmental hazard, decomposition of uranium radium-226: biological damage uranium-238: hazards of radon gas potassium-40: light radioactive elements, emit positron to form argon-40

half life of an isotope: 0.693/k fraction left: (1/2)^number of half-lives rate = KN K= constant N=number of radioactive nuclei Rate = number of nuclei that disintegrate per second ln (Nº/N†) = Kt Nº: original number of radioactive atoms N†: number of radioactive atoms left after t secs K: rate constant with units of s^-1 t: time in seconds from start of experiment