Nuclear and Particle Flashcards
Unified atomic mass unit
1/12th of the mass of a carbon 12 atom. 1amu = 1.661 *10^-27kg
Proton number Z
the number of protons inside a nucleus of a particular atom. Z
Nucleons number A
The number of nucleons (protons and neutrons) inside the nucleus of a particular atom
Isotopes
Atoms of the same element which contain the same number of protons but varying numbers of neutrons.
Alpha particle scattering conclusions
- vast majority of mass is centred in the nucleus
- the nucleus has positive charge
- nucleus diameter is considerably smaller than the diameter of the atom
The strong nuclear force
Acts between nucleons and holds the nucleus together against the electrostatic repulsion of the protons
Fundamental particles
Particles that cannot be broken down further
Hadrons
Whole number of charge due to quark charge. Examples are neutrons and protons
Leptons
Fundamental particles. Examples are electrons and neutrinos
A neutrino
A fundamental particle with almost no mass and no charge. Antiparticle = antineutron
Quarks
Components of hadrons, have a fractional electronic charge
The weak nuclear force
Felt by both quarks and leptons. Changed quarks from one type to another
Radioactive decay
Is the spontaneous and random decay of an unstable nucleus
Beta minus decay
Gives off an electron and a antineutrino
Beta plus decay
Gives off a positron and a neutrino
Alpha decay
Gives off an alpha particle and a gamma ray
Activity
The number of decays per unit time. Measured in becquerels
The decay constant λ
The probability that an individual nucleus will decay per unit time
Carbon decay
A technique used to determine the age of organic matter from the relative proportions of the carbon-12 and carbon-14 isotopes it contains using the half life of carbon-14
Annihilation
The process in which a particle and its antiparticle interact and their combined mass is converted to energy using E = mc^2
Binding energy
The minimum energy required to separate the nucleus
