Unit 3 Atomic Structure and Nuclear Chemistry
Smallest particle of an element
Particles found within the atom, mainly protons, neutrons, and electrons.
A subatomic particle that has a positive charge and that is found in the nucleus of an atom
A subatomic particle that has no charge and that is found in the nucleus of an atom
Negatively charged particle that exists in a cloud formation around an atom’s nucleus.
Number of protons
the sum of the number of neutrons and protons in an atomic nucleus
Average Atomic Mass
the average mass of the element’s isotopes, weighted according to the abundance of each isotope
An atom with the same number of protons and a different number of neutrons from other atoms of the same element.
A particle that is electrically charged (positive or negative)
Process by which certain unstable atoms or elements undergo spontaneous disintergration, or decay, in an effort to attain a more balanced nuclear state
Radiation that is made up of alpha particles; can be stopped by a piece of paper. only dangerous if eaten or inhaled
has a moderate penetrating ability and can be stopped by sheet metal of plywood
travels in waves, and is the least ionizing with highest penetration. Can only be blocked with lead.
a type of equation that shows the atomic number and mass number of the particles involved
Half – Life
The time it takes for half of the atoms of a radioactive element to decay.
A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
A nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy
Slows down fast neutrons to increase the chance of more reactions. (So they don’t pass through the nuclei)
Cadmium rod used in a nuclear reactor to absorb neutrons from fission
Device that measures radioactivity by producing an electric current when radiation is present; emits a clicking sound or flashing lights.
developed the atomic theory
discovered the electron
British physicist (born in New Zealand) who discovered the atomic nucleus and proposed a nuclear model of the atom (1871-1937)
Found that electrons move in a circular path around the nucleus