Ch. 20 Honors Chem

atomic number

atomic number

number of protons in the nucleus

mass number

number of protons and neutrons in nucleus

nucleon

particles inside the nucleus

isotopes

atoms having the same number of protons but different neutrons

radioactive decay

occurs due to nuclear instability, causes the nucleus to decay spontaneously

nuclear equation

equation in which we balance the atomic numbers and the mass numbers on both sides

true

T or F: in radioactive decay the mass of the products is less than the reactants

einstein equation

E=mc²; loss of mass results in release of energy

alpha decay

atomic number of the product decreased by two and the mass number of the product decreased by 4

beta particle

an electron that is released from the nucleus at high speeds; atomic number increases and mass number stays constant

beta decay

neutron being converted into a proton and electron

positron

same mass as an electron with the opposite charge; converts proton to a neutron

electron capture

electron being captured by the nucleus from an inner-orbital electron; atomic number of the product decreases and the mass number stays constant; accompanied by gamma rays

gamma rays

high energy photon of light that allows nuclei in an unstable state. this allows remaining nuclei to be more stable; 0 atomic and mass number

lead

often for heavy metals, the final step of the "decay series" is this element

nuclear transformations

conversion of one element into another

transuranium elements

elements from 93-118; they have been the fusion of lighter nuclei with either neutrons or positive ion bombardment to make heavier elements

geiger counter

a device that can be used to detect nuclear radioactivity

scintillation counter

device used to measure radioactivity by use of flashes of light made by decay particles

radioactive dating

a method for finding the ages of either living material (carbon bases) or non living material from the past; typically uses the nuclei carbon 14 or uranium 238

radiotracers

substances which can be introduced into organisms in food or drugs for the purpose of detecting or monitoring their radioactivity

important radioactive nuclides

iodine 131 for thyroid, sodium 24 for red blood cells, technetium 99m for bones

fission

breaking up of unstable nuclei into lighter nuclei; after the mass of the products is less than the "reactants"; energy is released

chain reaction

the fission process often produces extra neutrons which help to carry on the fission process called this

critical mass

the amount of fissionable material needed to produce a self-sustaining chain reaction

emission

product side

capture

reactant side