Elements and the Periodic Table

Science

alkali metal

elements in Group 1 of the periodic table, like lithium, sodium and potassium

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conductivity

the ability of a material to let heat or electricity pass through

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diatomic molecule

a particle consisting of two atoms

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group

elements in the same vertical column of the periodic table

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halogen

an element in Group 17 of the periodic table, like chlorine

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luster

the way a mineral's surface reflects light

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metal

an element that is a good conductor of heat and electricity

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metalloid

an element that shares properties with metals and nonmetals, like a semiconductor

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noble gas

an element in Group 18 of the periodic table, like helium, neon and argon

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nonmetal

an element that is a poor conductor of heat and electricity

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period

a horizontal row of elements of the periodic table

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periodic table

a chart of all the elements, arranged by their physical and chemical properties

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radioactive decay

the breakdown of an unstable atomic nucleus, this releases particles and energy

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radioactivity

the ability of an unstable nucleus to emit radiation

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semiconductor

a material that conducts electricity under certain conditions, it has properties of both metals and nonmetals

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transition element

an element in Group 3 to Group 12 of the periodic table, they are all metals

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