Chem Ch. 22

Front 1

nucleons

Back 1

protons and neutrons

Front 2

nuclide

Back 2

(an atom) defined by the number of protons and neutrons in the nucleus.

Front 3

mass defect

Back 3

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

Front 4

nuclear binding energy

Back 4

the energy released when a nucleus is formed from nucleons.

Front 5

binding energy per nucleon

Back 5

the binding energy of the nucleus divided by the number of nucleons it contains.

Front 6

band of stability*

Back 6

stable nuclei cluster over a range of neutron-proton ratios.

Front 7

nuclear shell model

Back 7

nucleons exist in different energy levels, or shells, in the nucleus.

Front 8

magic numbers

Back 8

The numbers of nucleons that represent completed nuclear energy levels - 2, 8, 20, 28, 50, 82 and 126

Front 9

nuclear reaction

Back 9

A reaction that affects the nucleus of an atom.

Front 10

transmutation

Back 10

a change in the identity of a nucleus as a result of a change in the number of its protons.

Front 11

radioactive decay

Back 11

the spontaneous disintegration of a nucleus into a slightly lighter and more stable nucleus, accompanied by emission of particles, electromagnetic radiation, or both.

Front 12

nuclear radiation

Back 12

particles or electromagnetic radiation emitted from the nucleus during radioactive decay.

Front 13

radioactive nuclide

Back 13

an unstable nucleus that undergoes radioactive decay.

Front 14

beta particle

Back 14

an electron emitted from the nucleus during some kinds of radioactive decay.

Front 15

alpha particle

Back 15

two protons and two neutrons bound together and is emitted from the nucleus during some kinds of radioactive decay

Front 16

positron

Back 16

a particle that has the same mass as an electron, but has a positive charge, and is emitted from the nucleus during some kinds of radioactive decay.

Front 17

electron capture

Back 17

an inner orbital electron is captured by the nucleus of its own atom.

Front 18

gamma rays

Back 18

high-energy electromagnetic waves emitted from a nucleus as it changes from an excited state to a ground energy state.

Front 19

half-life

Back 19

the time required for half the atoms of a radioactive nuclide to decay.

Front 20

decay series

Back 20

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

Front 21

parent nuclide

Back 21

the heaviest nuclide of each decay series.

Front 22

daughter nuclides

Back 22

the nuclides produced by the decay of the parent nuclides.

Front 23

artificial transmutations

Back 23

bombardment of stable nuclei with charged and uncharged particles.

Front 24

transuranium elements

Back 24

elements with more than 92 protons in the nuclei.

Front 25

roentgen

Back 25

a unit used to measure nuclear radiation; it is equal to the amount of radiation that produces 2x10^9 ion pairs when it passes through 1cm^3 of dry air.

Front 26

rem

Back 26

the quality of ionizing radiation that does as much damage to human tissue as is done by 1 radiation of high-voltage x rays.

Front 27

film badges

Back 27

use exposure of film to measure the approx. radiation exposure of people working with radiation.

Front 28

Geiger-Muller counters

Back 28

instruments that detect radiation by counting electric pulses carried by gas ionized by radiation.

Front 29

scintillation counters

Back 29

instruments that convert scintillating light to an electric signal for detecting radiation.

Front 30

radioactive dating

Back 30

the process by which the approx. age of and object is determined based on the amount of certain radioactive nuclides present.

Front 31

radioactive tracers

Back 31

radioactive atoms that are incorporated into substances so that movement of the substances can be followed by radiation detectors.

Front 32

nuclear fission

Back 32

a very heavy nucleus splits into more-stable nuclei of intermediate mass

Front 33

chain reaction

Back 33

a reaction in which the material that starts the reaction is also one of the products and can start another reaction.

Front 34

critical mass

Back 34

the minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction.

Front 35

nuclear reactors

Back 35

devices that use controlled-fussion chain reactions to produce energy or radioactive nuclides.

Front 36

nuclear power plants

Back 36

use heat from nuclear reactors to produce electrical energy.

Front 37

shielding

Back 37

radiation-absorbing material that is used to decrease radiation exposure from nuclear reactors, especially gamma rays.

Front 38

control rods

Back 38

neutron-absorbing rods that help control the reaction by limiting the number of free neutrons.

Front 39

moderators

Back 39

used to slow down the fast neutrons produced by fission.

Front 40

nuclear fusion

Back 40

light-mass nuclei combine to form a heavier, more stable nucleus.