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Atoms
Term | Definition |
---|---|
atom | the smallest particle into which an element can be divided and still be the same element |
electrons | negatively charged particles |
nucleus | a small, dense center that has a positive charge and is surrounded by moving electrons |
neutrons | uncharged particles |
electron cloud | the area around the nucleus |
atomic number | the number of protons in the nucleus |
mass number | the total number of protons and neutrons |
periodic table | Dmitri Mendeleev's arrangement of the elements |
chemical symbol | an abbreviation for the element's name |
average atomic mass | an atom's weighted average of the masses of all the naturally occurring isotopes of that element |
metals | elements that are shiny and conduct heat and electricity as well |
nonmetals | poor conductors of heat and electricity |
metalloids | elements that have some properties of metals and some properties of nonmetals |
group | the vertical columns on the periodic table |
period | the horizontal rows on the periodic table |