Chem Unit 14p - Nuclear Chemistry

Nuclear reactions

Rxns involving changes to the nucleus of an atom as opposed to its electrons

Strong nuclear force

The force that holds the nucleus together despite the fact that protons are repelling each other

Radioactive

These types of substance have an unstable nucleus that will undergo decay because they have too many protons repelling each other for the nuclear force to keep the nucleus together; These types of elements can occur naturally (e.g., atomic number >83) or

Alpha decay

The emission of alpha particles by atoms that have too many protons to be stable. Each lost particle results in the creation of an isotope that has a mass number that is 4 less than the parent atom and an atomic number that is 2 less; This type of radiati

Beta decay

The conversion of a neutron to a proton, which stays inside the nucleus, and an electron, which is ejected from the nucleus at high velocity. Each lost particle results in the creation of an isotope that has the same mass number as the parent atom but an

Gamma decay

The emission of gamma rays - a high energy stream of light (rays, not particles); This type of radiation is the most penetrating & most dangerous. It can pass deep into solid material, including body tissue. It is stopped only by heavy shielding (concrete

Nuclear equation

Shows how a nucleus gains or loses subatomic particles in a nuclear reaction; shows the atomic numbers and mass numbers of the atoms involved

Fission reaction

A reaction in which a large nucleus is split into two smaller nuclei. Energy is given off and 3 neutrons are shot out of the nucleus. Some of the atom's mass is converted to energy; the source of power for the atomic bomb, nuclear power plants

Nuclear chain reaction

A continuous series of fission reactions that produce a tremendous amount of energy

E=mc2

The formula used to calculate how much energy is released during nuclear fission and fusion reactions. Explains why such a small amount of mass can be converted to such a large amount of energy and why fission and fusion rxns produce far more energy per g

Fusion reaction

A reaction in which two small nuclei join to form a single large nucleus; the source of power for the sun and other stars.

Nuclear chemistry

The study of the properties and behavior of atomic nuclei

Nucleus

The tiny, dense center of the atom that contains protons and neutrons.

Electrostatic attraction

A force between particles with the same electrical charge that causes them to be pulled together

Electrostatic repulsion

A force between particles with opposite electrical charges that causes them to push apart from one another

Alpha particle

The emission from a radioactive nucleus that is composed of 2 protons and 2 neutrons in the form of a helium nucleus; emitted because the atom has too many protons to be stable; symbol: 4/2 He

Beta particle

A high velocity electron released from a radioactive nucleus; emitted because the atom has too many neutrons to be stable; symbol: 0/-1e

Half-life

Tthe length of time required for half of the radioactive atoms in a given sample to decay

Nuclear Decay Series

A series of radioactive decays that lead from a large unstable nuclide, such as uranium 238, to a stable nuclide, such as lead-206

Ionizing Radiation

Radiation with enough energy to dislodge electrons from atoms thus forming ions; capable of causing cancer (gamma, X-rays, UV)

Free Radicals

Atoms or molecules with one or more unpaired electrons that make the atom or molecule unstable and highly reactive

Carbon-14 dating

The process of estimating the age of once-living material by measuring the amount of a radioactive isotope of carbon present in the material

Radioactive Tracer

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

Control Rods

Neutron-absorbing material (Cd or B) inserted into spaces between fuel assemblies in nuclear reactors to regulate fission reactions.

Nuclear Reactor

A facility within a nuclear power plant that initiates and controls the process of nuclear fission in order to generate electricity.

Nuclear Energy

Energy released when atomic nuclei undergo a nuclear reaction such as the spontaneous emission of radioactivity, nuclear fission, or nuclear fusion.

Moderator

A substance in a nuclear reactor that slows neutrons as they pass through it

Positron

A high velocity anti-electron released from radioactive nuclei that have too few neutrons

Positron Emission

In radioactive nuclei that have too few neutrons, the conversion of a proton to a neutron, which stays in the nucleus, and a positron, which is elected from the nucleus

Electron Capture

In radioactive nuclei that have too few neutrons, the combination of an electron with a proton to produce a neutron, which stays in the nucleus

Fuel Rods

The pellets of uranium or other fissionable material that are placed in tubes, which, together with the control rods, form the core of the nuclear reactor

Nuclear Power Plant

A facility that uses heat from nuclear reactors to produce electrical energy

Antioxidant

a substance that combines with or otherwise neutralizes a free radical, thus preventing oxidative damage to cells and tissues