Chapter 3: Nuclear Chemistry

the positively charged protons and neutral neutrons contained in an atom’s densely packed nucleus

process of changing one element to another through radioactive decay

A spontaneous process in which unstable nuclei lose energy by emitting radiation

an unstable nucleus that undergoes radioactive decay

4/2He, mass#=-4, atomic#=-2…cannot penetrate dead skin, tissue, or paper

when nuclei have too many neutrons relative to protons, it emits a beta particle. it increases the number of protons and decreases the number of nuetrons…atomic number increases

a proton is converted to a neutron, a positron is emitted, the atomic number decreases by 1, the mass number stays the same

Radioactive process in which a nucleus captures an inner-shell electron that combines with a proton to form a neutron. As a result, the atomic number decreases by 1, but the atomic mass remains the same.

emits a very high energy photon. This is due to the nucleus reorganizing itself in a lower energy state, much like a photon is given off by an electron when it moves from a high energy level to a lower one. The nucleus does not change otherwise.

the time required for one half of the atoms of a radioisotope to emit radiation an decay products

the transformation of atoms of one element into atoms of another element as a result of a nuclear reaction, such as bombardment with neutrons

A machine that moves atomic nuclei at higher and higher speeds until they crash into one another, sometimes forming heavier elements.

German physicist who discovered x-rays and developed roentgenography (1845-1923)

(Roentgen Equivalent Man) the dosage of ionizing radiation that will cause the same amount of injury to human tissue as 1 roentgen of X-rays

technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains

a radioactive atom that is incorporated into a substance so that movement of the substance can be followed by a radiation detector

A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy

A nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy

the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction

relatively unstable form of Uranium; nuclear fission depends on it; more rare than U-238(92 protons and 143 neutrons)