Holt Chemistry NY: Chapter 18 – Nuclear Chemistry
nucleons
a proton or a neutron. The subatomic particles that are in the nucleus.
nuclide
an atom that is identified by the number of protons and neutrons in its nucleus. ex: “Carbon-14”
strong force
the interaction that binds nucleons together in a nucleus. It is the force of attraction between protons & neutrons.
mass defect
the difference between the mass of an atom and the sum of the masses of the atom’s protons, neutrons, and electrons. The mass of any actual atom is slightly less than the combined mass of its separated parts.
radioactivity
the process by which an unstable nucleus emits one or more particles of energy in the form of electromagnetic radiation.
beta particle
a charged electron emitted by a nucleus during fission & radioactive decay. has almost no mass and a negative charge. Medium penetrating power (stopped by aluminum foil)
gamma ray
the high energy photon emitted by a nucleus during fission and radioactive decay. has no mass or charge. Greatest penetrating power (stopped by thick concrete or lead)
alpha particle
a positively charged helium nucleus particle emitted by a nucleus during fission & radioactive decay. Weakest penetrating power (stopped by plastic sheeting or tissue paper)
Nuclear fission
the splitting of the nucleus of a large atom into two or more fragments, a process that produces a great deal of energy.
Nuclear fusion
the combination of the nuclei of small atoms to form a larger nucleus, a process that produces a great deal of energy.
Chain Reaction
a reaction in which a change in a single molecule makes many molecules change until a stable compound forms.
Critical mass
the minimum amount of a fissionable isotope that is needed to sustain a chain reaction.
Transmutation
the act of one radioactive element turning into a different element through the emission of alpha, beta, gamma, or positron radiation.
Half-Life
the time required for half of a sample of radioactive substance to disintegrate by radioactive decay or natural processes.
Isotope
an atom that has the same number of protons (atomic number) as other atoms of the same element but has a different number of neutrons (atomic mass).
atomic number
the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element. Also equals the # of positive charges in the nucleus
mass number
the sum of the numbers of protons and neutrons of the nucleus of an atom
N/Z ratio
determines the stability of an atom’s nucleus. If the value is between 1.0 and 1.5, then the nucleus will be stable. If the value is above or below that range, then the nucleus will be unstable and radioactive
control rod
a nuclear moderator that can control the rate of a fission reaction in a nuclear reactor. These are important safety devices that can stop a chain reaction from going out of control.
Apoptosis
means “cell death” and this is caused when a cell gets a heavy dose of radiation. Quickly dividing cells, like cancer cells, are especially vulnerable to radiation treatments. As a result radiation can be used to treat cancers, but can also cause sickness, or even birth defects and cancer.
quark
The particles that make up protons and neutrons
beta decay
A proton is turned into a neutron or vice versa (0_-1e)
electron capture
An unstable atom captures an electron and turns a proton into a neutron.
positron emission
positrons are given off to stabilize the atom
annihilation of matter
the process where positrons collie with electrons, destroying the two particles but producing gamma rays.
alpha decay
the release of alpha particles to stabilize the atom