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Science/ elements
periodic table of elements
Question | Answer |
---|---|
element | a pure substance that can't be separated or broken down into simpler substances by physical or chemical means |
nonmetals | elements that are dull & are poor conductors of thermal energy & electric current |
pure substance | a substance in which there is only one type of particle includes elements and compounds |
metalloids | elements that have properties of both metals & nonmetals; sometimes refered to as semi conductors |
metals | elemnts that are shiny and are good conductors of thermal energy & electric currrent; most metals are malleable & ductile |
periodic | elements that are ordered |
periodic law | states that the chemical or physical properties of elements are periodic functions of their atomic numbers |
period | a horizontal row on the periodic table |
group | a column of elements on the periodic table |
akali metals | the elements in group 1 of the periodic table; they are the most reactive metals |
akaline earth metals | the elements in group 2 of the periodic ; they are reactive but less reactive than the akali metals |
halogens | the elements in group 17 of the periodic table; they are very reactive nonmetals, & their atoms have 7 electrons in their outer level |
noble gases | the unreactive elements in group 18 of the periodic table; their atoms have 8 electrons on their outer level |