Science Atom Definitions Flashcards
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NUCLEUS OF ATOM
Center of an atom, consisting of the protons and neutrons bound together.
PROTON
A sub-atomic particle with a positive charge.
ISOTOPE
Atoms of the same element, that differ in the number of neutrons.
NEUTRON
A sub-atomic particle with no charge, it is neutral.
RADIOISOTOPE
A radioactive form of an isotope.
ELECTRON
A very light sub-atomic particle with a negative charge, it moves around the nucleus of an atom.
RADIOACTIVE
A property of elements where they are unstable and emit alpha, beta and/or gamma radiation. (This may change their identity).
ALPHA PARTICLE
Positively charged nuclei of helium atom, consisting of 2 protons and 2 neutrons. Emitted from unstable isotopes.
BETA PARTICLE
Positively or negatively charged with the same size and mass as electrons. Emitted from unstable isotopes.
GAMMA RAY/RADIATION
Extremely high energy electromagnetic radiation produced during nuclear reactions. It has no mass and travels at the speed of light.
HALF LIFE
The time taken for half the radioactive atoms in a sample to decay. That is, to change to atoms of a different element by emitting radiation.
COSMIC RADIATION
The naturally occurring radiation that comes from outer space.
NUCLEAR FISSION
Splitting of the nucleus of a large atom into 2 smaller atoms, several neutrons and emitting lots of heat and radiation.
BACKGROUND RADIATION
The naturally occurring radiation emitted by the earth, air and surroundings. Usually at very low levels.
RADIOCARBON DATING
A method of determining the age of a fossil using the remaining amount of unchanged radioactive carbon. All living things have a certain amount, which slowly changes after it dies.
