Chemistry – Atomic Structure and Nuclear Chemistry

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Alpha Particle
Consist of two protons and two neutrons and are identical to helium-4 nuclei.
Anion
A negatively charged ion; the type of ion that nonmetals become when they gain electrons.
Atom
The smallest representative particle of an element.
Atomic Mass Number
The total number of protons and neutrons in an atomic nucleus; can be noted by the symbol A; differs for different isotopes of the same element.
Atomic Mass Unit
The standard unit for indicating the mass of an atom on the atomic scale; is defined as 1/12 of the mass of a carbon-12 atom; can be noted by the symbols amu or u.
Atomic Number
The number of protons in the nucleus of an atom; is the same for all isotopes of the same element; is unique to an element and is used to distinguish one element from another; can be noted by the symbol Z.
Average Atomic Mass
Is the calculated average of all the atomic masses of all of the isotopes of the same element; is displayed on a periodic table under the element symbol.
Beta Particle
Energetic electrons emitted from the nucleus.
Cation
A positively charged ion; the type of ion that metals become when they lose electrons.
Electron
Subatomic particle that is negatively charged; located outside of the nucleus of an atom.
Energy Levels
The name for the levels of locations for electrons; are described by numbers: 1, 2, 3,4, 5,6,7.
Energy Sublevels
The subdivisions of energy levels to describe electron locations; designated by the letters: s, p, d, f
Fission
The splitting of large nucleus into two or more smaller nuclei.
Fusion
The joining of two lighter nuclei into a heavier nuclei.
Gamma Radiation
An energetic electromagnetic radiation coming from the nucleus of a radioactive atom; generated in stars when a positron and an electron collide during the fusion process.
Ion
A positively or negatively charged atom or group of atoms that has lost or gained one or more electrons.
Isotope
Different types of atoms of the same element that differ only by the number of neutrons, which gives a different mass number for elements of the same atomic number.
Neutron
Subatomic particle that is electrically neutral (neither positive nor negative); found in the nucleus of an atom.
Nucleus
The small, dense portion of an atom that consists of protons and neutrons.
Orbital
The subdivision of the energy sublevels to describe electron locations.
s sublevel
1 orbital in this sublevel
p sublevel
3 orbitals in this sublevel
d sublevel
5 orbitals in this sublevel
f sublevel
7 orbitals in this sublevel
Proton
Subatomic particle that is positively charged; located in the nucleus of an atom.
Radioactive Decay
The disintegration of an unstable nucleus that causes one or more new nuclei to form; typically emits alpha particles, beta particles, or gamma rays.
Valence Electron
The outermost electrons that are used in bonding.
Categories: Nuclear Chemistry