College Chemistry Chapter 19: Nuclear Chemistry

Vocabulary practice flashcards covering fundamental nuclear chemistry concepts from Chapter 19, including types of radioactive decay, reaction comparisons, key historical figures, half-lives, binding energy, fission, and fusion.

Neutron-to-Proton Ratio (Light Elements)

The ratio that determines nuclear stability; it is exactly $1:1$ for the first $20$ elements.

Radioactivity Threshold ($84$ Protons and Up)

The point of nuclear instability where nuclei with greater than $83$ protons ($84$ protons and up) are all unstable and radioactive.

Belt of Stability

The region on a graph of neutrons versus protons where all non-radioactive (stable) isotopes are represented.

Geiger Counter

An instrument used to detect ionizing radiation.

Nuclear Transmutation

The conversion of one chemical element or isotope into another, which can be induced through extremely high-energy collisions.

Henri Becquerel

The scientist who discovered radioactivity using uranium salts on photographic plates; the SI unit for radioactive decay ($\text{Bq}$) is named after him.

Ernest Rutherford

The physicist famous for the gold foil experiment who discovered that radon was a byproduct of nuclear decay and transmutation.

Marie Curie

The scientist who coined the term radioactivity, quantized radioactivity, and discovered polonium ($\text{Po}$) and radium ($\text{Ra}$) from uraninite mineral.

Chemical Reactions

Processes where atoms are rearranged by breaking and forming chemical bonds involving only orbital electrons, absorbing or releasing relatively small amounts of energy, with rates influenced by temperature, pressure, concentration, and catalysts.

Nuclear Reactions

Processes where elements are converted from one to another involving protons ($\text{P}^+$), neutrons ($\text{N}^0$), electrons ($e^-$), and other elementary particles, releasing tremendous amounts of energy, with rates completely uninfluenced by temperature, pressure, or catalysts.

Alpha Decay ($^4_2\alpha$)

A decay mode emitting a particle identical to a helium nucleus ($2$ protons and $2$ neutrons) that decreases both protons and neutrons by $2$ ("Down 2"); it travels only a few centimeters, can be stopped by tissue paper, and is dangerous if ingested.

Beta Decay ($^0_{-1}\beta$)

A decay mode where a neutron converts into a proton without gaining mass and emits an electron-identical beta particle ($e^-$), increasing the atomic number by $1$ ("Up 1"); it can be stopped by metal or skin.

Gamma (\gamma) Decay

A high-energy form of electromagnetic radiation with no mass loss that has the greatest penetration ability, is extremely dangerous, and may accompany other decay modes.

Neutron Capture

A nuclear decay process that increases the mass of an isotope and changes the isotope's identity without altering the element.

Spontaneous Fission

A type of decay generally occurring only in very heavy elements, characterized by a large split of protons ($\text{P}^+$) and/or loss of neutrons.

Half-Life

A measure of atomic decay representing the duration of time required for one-half ($1/2$) of the starting radioactive material to decay exponentially.

Radiocarbon Dating

An absolute dating method based on the ratio of carbon-$14$ to carbon-$12$ ($^{14}\text{C}/^{12}\text{C}$), which remains constant during an organism's life but decreases steadily after death; only applies to once-living matter.

Nuclear Binding Energy

The energy required to overcome the strong nuclear force to break up a nucleus into separate nucleons (protons and neutrons).

Mass Defect

The change in mass between separate nucleons and the formed nucleus, representing the mass converted directly into nuclear binding energy.

Nuclear Fission

The splitting of larger nuclei into smaller fragments at normal temperatures, releasing large amounts of energy; it can be sustainably harnessed for commercial electricity in nuclear power plants and advanced submarines.

Nuclear Fusion

The process of combining small nuclei into larger ones, releasing more energy than fission ($\text{fusion} > \text{fission}$); it requires extremely high temperatures and is utilized in hydrogen bombs and particle accelerators.

Iron ($\text{Fe}$)

The chemical element least likely to undergo nuclear fusion.

Nuclear Chain Reaction

A self-sustaining sequence of nuclear fission reactions where each reaction produces particles that induce further fission events.

Control Rods

Reactor components used to regulate fission rates; they do not provide an abundance of extra neutrons to speed up the nuclear reaction.

Critical Mass

The minimum mass of fissionable material required to generate and sustain a self-sustaining nuclear chain reaction.

Induced Transmutation

The creation of trans-uranium elements by colliding smaller atoms at tremendous speeds inside particle accelerators ("atom smashers") to fuse them into larger nuclei.