Hcib Chemistry Chapter 21 Vocabulary - Glossary Definitions

Front 1

Nucleon

Back 1

A proton or neutron.

Front 2

Nuclide

Back 2

An atom that is identified by the number of protons and neutrons and its nucleus.

Front 3

Mass defect

Back 3

The difference between the mass of an atom and the sum of the masses of the atom's protons, neutrons, and electrons.

Front 4

Nuclear binding energy

Back 4

The energy released when a nucleus is formed from nucleons.

Front 5

Nuclear shell model

Back 5

A model which represents nucleons as existing in different energy levels, or shells, in the nucleus.

Front 6

Magic numbers

Back 6

The numbers (2,

8, 20, 28, 50,

82, and 126) that represent the number of particles in an extra stable atomic nucleus that has completed shells of protons and neutrons.

Front 7

Nuclear reaction

Back 7

A reaction that affects the nucleus of an atom.

Front 8

Radioactive decay

Back 8

The disintegration of an unstable atomic nucleus into one or more different nuclides, accompanied by the emission of radiation, the nuclear capture or ejection of electrons, or fission.

Front 9

Nuclear radiation

Back 9

The particles that are released from the nucleus during radioactive decay, such as neutrons, electrons, and protons.

Front 10

Radioactive nuclide

Back 10

A nuclide that contains isotopes that decay and that emit radiation.

Front 11

Alpha particle

Back 11

A positively charged atom that is released in the disintegration of radioactive elements and that consists of two protons and two neutrons.

Front 12

Beta Particle

Back 12

A charged electron emitted during certain types of radioactive decay, such as beta decay

Front 13

Positron

Back 13

A particle that has the same mass and spin as an electron but that has a positive charge.

Front 14

Electron capture

Back 14

The process in which an inner orbital electron is captured by the nucleus of the atom that contains the electron.

Front 15

Gamma ray

Back 15

The high-energy photon emitted by a nucleus during fission and radioactive decay.

Front 16

Half-life

Back 16

The time required for half of a sample of radioactive substance to disintegrate by radioactive decay or by natural processes.

Front 17

Decay series

Back 17

A series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached.

Front 18

Parent nuclide

Back 18

A radionuclide that yields a specific daughter nuclide as a later member of a radioactive series.

Front 19

Daughter nuclide

Back 19

A nuclide produced by the radioactive decay of another nuclide.

Front 20

Artificial transmutation

Back 20

The transformation of atoms of one element into atoms of another element as a result of a nuclear reaction,

Such as bombardment with neutrons.

Front 21

Transuranium element

Back 21

A synthetic elements whose an atomic number is greater than that of uranium.

Front 22

Roentgen

Back 22

A unit of radiation does of X Rays or gamma rays that is equal to the amount of radiation that will produce 2.58 x 10^-4 of ions per kilogram of air at atmospheric pressure.

Front 23

Rem

Back 23

The quantity of ionizing radiation that does as much damage to human tissue as 1 roentgen of high-voltage X rays does.

Front 24

Film badge

Back 24

A device that measures the approximate of radiation received in a given period of time by people who work with radiation.

Front 25

Geiger-Müller counter

Back 25

An instrument that detects and measures the intensity of radiation by counting the number of electric pulses that pass between the anode and the cathode in a tube filled with gas.

Front 26

Scintillation counter

Back 26

An instrument that converts scintillating light into an electrical signal for detecting and measuring radiation.

Front 27

Radioactive dating

Back 27

The process by which the approximate age of an object is determined based on the amount of certain radioactive nuclides present.

Front 28

Radioactive tracer

Back 28

A radiactive material that is added to a substance so that its distributuion can be dected later.

Front 29

Nuclear waste

Back 29

Waste that contains radioisotopes.

Front 30

Nuclear fission

Back 30

The splitting of the nucleus of a large atom into two or more fragments; releases additional neutrons and energy.

Front 31

Chain reaction

Back 31

A continous series of nuclear fission reactions.

Front 32

Crtical mass

Back 32

The minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction

Front 33

Nuclear reactor

Back 33

A device that uses controlled nuclear reactions to produce energy or nuclides.

Front 34

Nuclear power plant

Back 34

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

Front 35

Shielding

Back 35

A radiation-absorbing material that is used to decrease radiation leakage from nulcear reactors.

Front 36

Control rod

Back 36

A neutron-absorbing rod that helps control a nulcear reation by limiting the number of free neutrons.

Front 37

Moderator

Back 37

A material that shows the velocity of neutrons so that they may be absirbed by the nuclei.

Front 38

Nuclear fusion

Back 38

The combination of the nuclei of small atoms to form a larger nucleus; releases energy.