Atomic and nuclear processes Flashcards
nucleus
small, dense region consisting of protons and neutrons at the centre of the atom. Protons are positively charged and neutrons are electrically neutral.
quarks
form composite particles called hadrons, such as protons and neutrons. All observable matter is made of up quarks, down quarks and electrons
proton in quarks
two up quarks and one down quark
neutron in quarks
one up quark and two down quarks
nuclear fusion
two or more nuclei are combined with high energy and temperature, to form different atomic nuclei. This process releases vast amounts of energy.
nuclear fission
heavy isotopes are split apart when unstable, into two smaller and more stable nuclei
nuclear decay
Random process where a nucleus loses energy by emitting radiation
alpha
helium nuclei, 2 protons and 2 neutrons
beta
electrons or positrons, proton -1 and neutrons 0
gamma
high energy photons, high energy wave
activity
number of decays per second in a given sample
alpha decay
alpha particle given off, neutrino given off
beta + decay
releases a positively charged beta particle (positron) and a neutrino.
beta - decay
releases an electron and an antineutrino
gamma decay
The nucleus goes from a high energy state to a lower energy state through the emission of electromagnetic radiation (photons). The proton and neutron number don’t change, so the parents and daughter atoms are the same element.
atomic mass unit
It is defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest
background radiation
measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources. Background radiation originates from a variety of sources, both natural and artificial
fission
Heavy and unstable isotopes are split apart into two smaller nuclei and gives off energy
fusion
The combination of two or more particles to form different atomic nuclei
half life
The time taken for radiation to decay by half
radioactive dating
technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.
chain reaction
process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats