A row in a periodic table of elements; the time required for one complete cycle of periodic motion; a unit of geological time into geologists divide eras.
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Noble Gases
Front
The elements in Group 8A of the periodic table.
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Neutron
Front
A neutral subatomic particle that is found in the nucleus of an atom.
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Electron Cloud
Front
A visual model of the most likely locations for the electrons in an atom.
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Transition Metals
Front
Elements that form a bridge between elements on the left and right sides of the periodic table.
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Proton
Front
A positively charged subatomic particle that is found in the nucleus of an atom.
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Valence Electron
Front
An electron that is in the highest occupied energy of an atom.
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Group
Front
A column of elements in a periodic table.
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Nonmetals
Front
Elements that are poor conductors of heat and electric current.
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Nucleus
Front
The dense, positively charged mass located in he center of an atom.
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Quarks
Front
A subatomic particle theorized to be among the basic units of matter.
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Alkaline Earth Metals
Front
The elements in Group 2A of the periodic table.
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Energy Levels
Front
The possible energies that electrons in an atom can have.
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Metals
Front
Elements that are good conductors of heat and electric current.
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Orbital
Front
A region of space around the nucleus where an electron is likely to be found.
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Isotopes
Front
Atoms of a given element that have different numbers of neutrons and different mass numbers.
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Halogens
Front
The elements in Group 7A of the periodic table.
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Electron
Front
A negatively charged subatomic particle that is found in the space outside the nucleus of an atom.
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Periodic Law
Front
The pattern of repeating properties displayed by elements in the periodic table.
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Metalloids
Front
Elements with properties that fall between those of metals and nonmetals.
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Mass Number
Front
The sum of the number of protons and neutrons in the nucleus of an atom.
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Atomic Mass Unit
Front
One twelfth the mass of a carbon-12 atom.
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Atomic Number
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A unique number for each element that equals the number of protons in an atom of that element.
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Alkali Metals
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The elements in Group 1A of the periodic tale, not including hydrogen.
