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extent to which a test measures what it claims to measure


the smallest component of an element having the chemical properties of the element

Atomic Symbol

an abbreviation for an element derived from the first one or two letters of the elements name


the core of an atom, consisting of two basic subatomic particles-protons and neutrons

Atomic Number

the number that designates the identity of an element, which is the number of protons in the nucleus

Mass Number

the number associated with an atom that is the same as the number of protons plus neutrons in its nucleus


electric charge=positive charge
Location in an atom=atomic nucleus


electric charge=electrically neutral
location in an atom=atomic nucleus


electric charge=negative charge
location in an atom=negative charged particles


a fundamental material consisting of only one type of atom


a material in which atoms of different elements are chemically held to one another


element that is generally shiny, opaque, malleable, ductile and a good conductior of electricity and heat


(18 on Period Table) exhibits both metallic and non metallic properties


an element that is nonmalleable, non ductile, and a poor conductor of electricity and heat

Periodic Table

highly organized chart listing all the known elements


a vertical column in the periodic table


a horizontal column in the periodic table

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