Nuclear Chemistry

All nuclei with atomic numbers greater than ___ are radioactive, most emit alpha particles

83

Isotopes with too many neutrons decay by ___

decay by beta decay

Isotopes with too many protons decay by ___

decay by positron emission or electron capture (positron more likely with smaller atoms)

Stable (“magic”) numbers of protons/neutrons

2, 8, 20, 28, 50, 82, 126 (neutron only)

Alpha Decay

loss of helium nucleus ^4₂ He, causes atomic number & mass to go down

Mass number

Number of protons + neutrons, top number to the left of an element

Atomic number

Number of protons, bottom number to the left of an element

Beta Decay

loss of an electron, aka beta particle: _⁰-1 e, atomic number goes up

Gamma radiation

loss of y-ray, represents energy lost

Positron emission

loss of a positron (opposite charge of electron): ^0₁ e, atomic number goes down

Electron capture

Addition of an electron to a proton in the nucleus, add ⁰_-1 e to the atom, atomic number goes down

Nuclear transmutation

Happens when you do something to accelerate a particle to collide it with the nuclide

Particle accelerator

Enormous devices that perform nuclear transmutations, usually using ⁴₂ He as the bombarding particles

Transuranium elements

Elements after uranium were discovered by bombarding uranium isotopes with neutrons

Nuclear Equation for Nuclear Transmutation

Radioactive decay equation

0.693/k = t_1/2 & ln(N_t/N₀) = -kt

nuclear fission

heavy nucleus splits into two smaller nuclei, releases energy

nuclear fusion

light nuclei fuse into one nucleus, releases energy

nuclear chain reaction

neutrons get bombarded and cause other neutrons to undergo fission

critical mass

minimum mass that must be present for a chain reaction to be sustained

supercritical mass

when more than critical mass is present, causes explosions

fuel rods

provide nuclear reactor with fuel

control rod

block some neutron paths, prevent reactor from reaching supercritical mass