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Term | Definition |
---|---|
element | matter made up of only one kind of atom 90 are natural 25+ are man made /synthetic |
periodic table | a chart to organize the elements |
symbol | 1-3 letters which represent an element |
periods | the rows; they have the same number of energy levels |
columns | groups; they have similar properties |
atomic number | number of protons in the nucleus of each atom of an element identifies the element |
isotopes | atoms of the same element with different numbers of neutrons |
mass number | number of protons plus number of neutrons |
atomic mass | weighted average mass of isotopes of an element unit is atomic mass unit(u) |
metals | elements that are malleable,ductile,good conductors of electricity and heat, and are generally shiny(metallic luster) they arre solids at room temperature |
nonmetals | elements that are usually gases or brittle solid and are poor conductors of electricity and heat many are not solid at room temperature |
metalliods | elements with characteristics of both metals and nonmetals they are solid at room temperature |