Nuclear Chemistry chapter 5

Flashcards covering key vocabulary from the 'Nuclear Chemistry' lecture, including definitions for natural radioactivity, types of radiation, radiation effects and protection, nuclear reactions (decay, fission, fusion), and radioactivity measurement concepts like half-life.

Radioactivity

The spontaneous breakdown of unstable nuclei to form a stable nucleus by emitting small particles of energy called radiation.

Unstable nucleus

Nuclei found in elements like carbon, hydrogen, and those with atomic numbers 20 and higher, which undergo radioactivity.

Radiation

Small particles of energy (such as alpha particles, beta particles, positrons, or gamma rays) emitted during radioactivity.

Radioisotope

An isotope of an element that emits radiation and includes its mass number in its name (e.g., iodine-131).

Alpha particle

A type of radiation identical to a helium nucleus (consisting of two protons and two neutrons), symbolized as
4
2He or
α.

Beta particle

A type of high-energy electron radiation, symbolized as
0
-1e or
β.

Positron

A type of radiation that is a positively charged electron (the antiparticle of an electron), symbolized as
0
+1e or
β+.

Gamma ray

A type of pure energy radiation emitted from an unstable nucleus, symbolized as
0
0
γ.

Ionizing radiation

Radiation that strikes molecules, knocking away electrons to form unstable ions, which can cause undesirable chemical reactions and damage rapidly dividing cells, potentially leading to cancer.

Radiation protection

Methods used to block different types of radiation, such as paper and clothing for alpha particles, lab coats or gloves for beta particles, and dense shielding like lead or concrete for gamma rays.

Radioactive decay

A process where an unstable nucleus breaks down by emitting radiation to become a more stable nucleus.

Nuclear equation

A representation of radioactive decay or other nuclear reactions where the sums of the mass numbers and the atomic numbers are equal on both sides of the equation (for reactants and products).

Alpha decay

A type of radioactive decay where a nucleus emits an alpha particle, resulting in a new nucleus with its mass number decreased by 4 and its atomic number decreased by 2.

Beta decay

A type of radioactive decay where a nucleus emits a beta particle, resulting in a new nucleus that has the same mass number but an atomic number that increases by 1.

Positron emission

A type of radioactive decay where a proton is converted to a neutron and a positron is emitted, resulting in a new nucleus with the same mass number but an atomic number that decreases by 1.

Gamma radiation (emission)

The emission of pure energy from an unstable nucleus, which does not change the mass number or the atomic number of the new nucleus.

Geiger counter

A common instrument used to detect alpha particles, beta particles, and gamma rays by using ions produced by radiation to create an electrical current.

Dosimeter

A device used to detect and measure the amount of radiation exposure from X-rays, gamma rays, and beta particles.

Half-life

The time required for the radiation level or the amount of a radioisotope to decrease (decay) to one-half of its original value.

Nuclear fission

The process where the nucleus of a heavy atom splits into two or more smaller nuclei, releasing a large amount of energy.

Nuclear chain reaction

A process that occurs during nuclear fission where the fission of each U-235 atom produces neutrons that then cause the nuclear fission of more and more U-235 atoms, leading to a self-sustaining reaction.

Nuclear fusion

Reactions that occur at extremely high temperatures, combining small nuclei into larger nuclei and releasing vast amounts of energy, such as those occurring in the sun and stars.