Nuclear Chemistry

An electrically neutral particle found in the nucleus with a mass almost that of the proton. In the fission process, neutrons are liberated. On bombarding O-18 nuclei with H-1 nuclei,produces F-18 with the emission of neutron.

The becquerel is a unit used to measure a radioactivity. One becquerel is that quantity of a radioactive material that will have 1 transformations in one second. Often radioactivity is expressed in larger units like: thousands (kBq), one millions (MBq) or even billions (GBq) of a becquerels. As a result of having one becquerel being equal to one transformation per second, there are 3.7 x 1010 Bq in one curie.

Thallium-201 is used in medicine to create images of the heart.

Beta decay occurs when the neutron to proton ratio is too great in the nucleus and causes instability. In basic beta decay, a neutron is turned into a proton and an electron. The electron is then emitted. e.g. hydrogen-3.C-14 & N-16 undergo radioactive decay by beta decay.

Yttrium-90 undergoes beta decay.Its half life is 64.1 hours .It is used in liver cancer therapy.

A light-year is a unit of length used by astronomers to measure interstellar distance (the distance between stars). A light-year is defined as the distance that light will travel in a year.

The term gamma ray is used to denote electromagnetic radiation from the nucleus as a part of a radioactive process. The energy of nuclear radiation is extremely high because such radiation is born in the intense conflict between the nuclear strong force and the electromagnetic force, the two strongest basic forces.

Phosphorus-32 and -33 are used to label the basic units of DNA or nucleotides.

All the above mentiones fields uses radioactive isotopes.

It is an energetic photon or light wave in the same electromagnetic family as light and x-rays, but is much more energetic and harmful. It is capable of damaging living cells as it slows down by transferring its energy to surrounding cell components. Gamma ray sources are used to find flaws in pipes and vessels and to check the integrity of welds in steel.

U-238, is fissionable but not fissile.It undergoes induced fission when impacted by an energetic neutron. But too few of the neutrons produced by U-238 fission are energetic enough to induce further fissions in it, so no chain reaction is possible with this isotope. Instead, bombarding 238U with slow neutrons causes it to absorb them (becoming 239U) .

Magnetic resonance imaging (MRI) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. The images can then be examined on a computer monitor, transmitted electronically, printed or copied to a CD. MRI does not use ionizing radiation.

Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei), often producing free neutrons and photons (in the form of gamma rays), as well. Fission of heavy elements is an exothermic reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments.

It is an energetic photon or light wave in the same electromagnetic family as light and x-rays, but is much more energetic and harmful. It is capable of damaging living cells as it slows down by transferring its energy to surrounding cell components. The Rs - 500 note detects energetic gamma rays through the case walls. Gamma ray sources are used to find flaws in pipes and vessels and to check the integrity of welds in steel.

All are the particle accelerators.

Beta rays are much lighter energy particles. The beta particles are energetic electrons given off by the nucleus of unstable isotopes to restore energy balance. They leave the nucleus at a speed of 270,000 kilometres per second.

Nuclear transmutation is the conversion of one chemical element or isotope into another. This occurs either through nuclear reactions (in which an outside particle reacts with a nucleus), or through radioactive decay (where no outside particle is needed).

A nuclear chain reaction occurs when one nuclear reaction causes an average of one or more nuclear reactions, thus leading to a self-propagating number of these reactions. The specific nuclear reaction may be the fission of heavy isotopes (e.g. 235U) or the fusion of light isotopes (e.g. 2H and 3H.)

The term ionization energy (EI) of an atom or molecule means the energy needed to remove electrons from an atom. Large atoms require low ionization energy while small atoms require high ionization energy.

The alpha particle is the heaviest. It is produced when the heaviest elements decay. Alpha and beta rays are not waves. They are high-energy particles that are expelled from unstable nuclei. In the case of alpha radiation, the energy of the particles leave the nucleus . An alpha particle is an helium atom and contains two neutrons and two protons. It leaves the nucleus of an unstable atom at a speed of 16,000 kilometres per second.

The rem is a unit used to derive a quantity called equivalent dose. This relates the absorbed dose in human tissue to the effective biological damage of the radiation. Not all radiation has the same biological effect, even for the same amount of absorbed dose. Equivalent dose is often expressed in terms of thousandths of a rem, or mrem. To determine equivalent dose (rem), you multiply absorbed dose (rad) by a quality factor (Q) that is unique to the type of incident radiation. For gamma rays and beta particles, 1 rad of exposure results in 1 rem of dose.

By utilizing the radioactive properties of Americium-241, smoke from a fire can be detected at a very early stage so it is used in smoke detectors. This early warning capability has saved many lives.

The roentgen is a unit used to measure a quantity called exposure. The roentgen measures the energy produced by gamma radiation in a cubic centimeter of air. This can only be used to describe an amount of gamma and X-rays, and only in air. One roentgen is equal to depositing in dry air enough energy to cause 2.58E-4 coulombs per kg. It is a measure of the ionizations of the molecules in a mass of air.

Beta decay occurs when the neutron to proton ratio is too great in the nucleus and causes instability. In basic beta decay, a neutron is turned into a proton and an electron. The electron is then emitted. e.g.hydrogen-3.

Chlorine-36 emitts beta particles.Its half life is 301,000 years.It is used in the measurement of sources of chloride and determining the age of water up to about 2 million years old.It is a naturally occurring radioisotope .