Nuclear Chemistry

Chapter 17: Terms

Enrico Fermi

founder of nuclear chemistry

nuclear chemistry

study of reactions involving the nucleus

nucleus

dense center of the atom; contains protons and neutrons

chemical reactions

changes in the electron shells of an atom

nuclear reactions

changes in the nucleus of an atom

Henri Becquerel

discovered radioactivity

Wilhelm Roentgen

discovered x-rays

Pierre and Marie Curie

discovered radium and polonium; coined the term radioactivity

protons

positively chared particles in an atom’s nucleus

neutrons

uncharged particles in the nucleus of an atom

atomic number

number of protons in the nucleus

mass number

number of protons and neutrons in the nucleus

isotopes

atoms of the same element but have a different number of neutrons

stable

describes atoms and isotopes that show no tendency to break up or suddenly change into other elements

unstable

nuclei with tendency to spontaneously shed subatomic particles or otherwise break apart

nuclear radiation

high-energy particles and electromagnetic waves produced by a nuclear reaction

radioactivity

phenomenon in which any sample of an unstable element continually emits energy as its atoms decay

radioactive

describes unstable substances that continually emit energy as their atoms decay

nuclide

specific type of atom described by both its atomic number and its mass number

radioactive nuclides

include isotopes of all elements that are radioactive

alpha and beta rays

produced by naturally radioactive elements, consist of subatomic particles moving at high speed

alpha particle

clump of 2 protons and 2 neutrons

beta particle

high-speed electron

gamma rays

high-energy electromagnetic waves

dense

nucleus is ___

strong nuclear force

force that holds protons and neutrons together in an atomic nucleus

radioactive decay

conversion of one nuclide into another in a spontaneous nuclear reaction

nuclear mass defect

phenomenon in which the mass of an atom is measurably less than the total mass of the individual particles

Albert Einstein’s theory of relativity

E=mc² (energy = mass x speed of light²)

law of conservation of mass and energy

restatement of the law of conservation of energy; includes the relationship between matter and energy; states that matter and energy can neither be created nor destroyed, only changed from one form to another

nuclear binding energy

amount of energy necessary to break a nucleus into its component nucleons

electron volt (eV)

energy unit equal to kinetic energy gained by an electron when it is accelerated through an electron potential difference of 1 V

binding energy per nucleon

binding energy divided by number of nucleons

chemical equations

these describe chemical reactions

alpha decay

nuclear decay that occurs when an unstable atom ejects a clump of 2 protons and 2 neutrons (an alpha particle) in order to reach a more stable state

beta decay

nuclear decay that occurs when a neutron in an atom’s nucleus changes into a proton and emits an electron (a beta particle) in the process

gamma decay

form of nuclear decay that releases electromagnetic waves of very high frequency and energy

gamma radiation

electromagnetic waves of very high frequency and energy

neutron radiation

radiation that consists of neutrons ejected from an atomic nucleus

production of transuranium elements

the cheif use of neutron radiation is ____

half-life (t_1/2)

length of time it takes for half of an original substance to decay into a new substance (or isotope)

activity

rate of decay occurring in a radioactive substance

Becquerel (Bq)

SI unit of activity, equal to one nuclear disintegration per second

Curie (Ci)

non-SI unit of activity, equal to 37 billion disintegrations per second

daughter element

substance resulting from the parent elements changing in nuclear decay

radioactive decay series

chain of radioactive nuclides that decay into other nuclides, ultimately ending in a nonradioactive nuclide

radiometric dating

inferring the age of a sample from the relative amounts of parent and daughter isotopes

bombardment reactions

nuclear reactions induced by pelting a sample with other particles

nuclear reactors and cyclotrones

bombardment reactions use these

transuranium elements

elements with higher atomic numbers than uranium

ionizing radiation

any radiation capable of causing ionization (alpha rays, beta rays, gamma rays, x-rays, and neutrons)

radiation burns

skin burns that can result from direct contact with beta-emitting isotopes

Geiger counter

best-known type of radiation detector

absorbed dose

energy an object has absorbed from radiation

Gray (Gy)

SI unit of absorbed dose; the absorption of 1 Joule of radiation energy per kilogram of mass

rad (radiation absorbed dose)

non-SI unit of absorbed dose; absorption of 0.01 Joule of radiation energy per kilogram of mass

biological dose equivalent

quantity of radiation exposure that takes into account how different types of radiation affect living things

sievert (Sv)

SI unit of biological dose equivalent; the amount of radiation that will cause the same biological injury as 1 Gray of x-rays or gamma rays

rem

non-SI unit of biological dose equivalent; amount of radiation that will cause the same biological injury as 1 rad of x-rays or gamma rays

Enrico Fermi

made the first self-sustaining reaction; speculated that if one bombards uranium with neutrons, he could make new, higher atomic-numbered elements

Lise Meitner and Otto Frisch

discovered nuclear fission

Otto Hahn

this scientist’s experiments were the basis of Meitner and Frisch’s determinations

nuclear fission

nuclear reaction in which an atom is split into 2 smaller atoms

chain reaction

the phenomenon in which a nucleus of one element can cause other nuclei to fission, thereby producing more neutrons, which can cause other nuclei to fission, and so on…

critical mass

minimal amount and density of a fissionable element needed for a chain reaction to occur

self-sustaining

describes a reaction that has enough critical mass

nuclear reactor

device for safely initiating and controlling a fission chain reaction

enrichment

process of increasing the content of fissionable isotopes in a uranium sample to make a critical mass possible

moderator

water or graphite that slows down the neutrons so they are easier to be captured by the fissionable material

coolant

removes the excess heat from the reactor

control rods

absorb the neutrons to stop or slow down the reaction of fission

containment vessel

heavy steel and concrete dome that surrounds a nuclear reactor

loss of coolant accident

nuclear-powered accident in which a pipe rupture, pump failure, or other breakdown deprives the core of coolant, possibly causing the core to overheat

meltdown

situation in which the core of a nuclear reactor overheats so badly that the fuel melts through the bottom of the pressure vessel

reprocessing

nuclear fuel recycling

breeder reactor

nuclear reactor that produces more fissionable fuel than it uses

Chernobyl

worst nuclear accident in history occured here

Fukushima Daiichi

the world’s second worst nuclear accident occured here

Three Mile Island

world’s first big nuclear accident

nuclear fusion

nuclear reaction in which light nuclei are combined into a heavier one

plasma

atoms undergoing fusion are usually in this state

thermonuclear reactions

high-temperature nuclear fusion reactions

Edward Teller

made the world’s first thermonuclear weapon

hydrogen bomb

an example of a thermonuclear weapon is ____

magnetic confinement and inertial confinement

2 ways of confining a fusion reaction