Unit 3 Atomic Structure and Nuclear Chemistry

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Atom
Smallest particle of an element
Subatomic Particle
Particles found within the atom, mainly protons, neutrons, and electrons.
Proton
A subatomic particle that has a positive charge and that is found in the nucleus of an atom
Neutron
A subatomic particle that has no charge and that is found in the nucleus of an atom
Electron
Negatively charged particle that exists in a cloud formation around an atom’s nucleus.
Atomic Number
Number of protons
Mass Number
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
Isotope
An atom with the same number of protons and a different number of neutrons from other atoms of the same element.
Ion
A particle that is electrically charged (positive or negative)
Radioactivity
Process by which certain unstable atoms or elements undergo spontaneous disintergration, or decay, in an effort to attain a more balanced nuclear state
Alpha Radiation
Radiation that is made up of alpha particles; can be stopped by a piece of paper. only dangerous if eaten or inhaled
Beta Radiation
has a moderate penetrating ability and can be stopped by sheet metal of plywood
Gamma Radiation
travels in waves, and is the least ionizing with highest penetration. Can only be blocked with lead.
Nuclear Equation
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.
Nuclear Fission
A nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
Nuclear Fusion
A nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy
Moderator
Slows down fast neutrons to increase the chance of more reactions. (So they don’t pass through the nuclei)
Control Rods
Cadmium rod used in a nuclear reactor to absorb neutrons from fission
Geiger Counter
Device that measures radioactivity by producing an electric current when radiation is present; emits a clicking sound or flashing lights.
Dalton
developed the atomic theory
Thomson
discovered the electron
Rutherford
British physicist (born in New Zealand) who discovered the atomic nucleus and proposed a nuclear model of the atom (1871-1937)
Bohr
Found that electrons move in a circular path around the nucleus
Categories: Atomic Physics