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Atoms/Periodic Table
Term | Definition |
---|---|
atomic number | Number of protons and electrons in an atom |
atomic mass | total weight of protons and neutrons (protons + neutrons) |
atom | smallest unit of matter |
neutron | A subatomic particle that has no charge and that is found in the nucleus of an atom |
proton | A subatomic particle that has a positive charge and that is found in the nucleus of an atom |
electron | A subatomic particle that has a negative charge |
electron cloud | mostly empty space; area outside the nucleus where electrons are found |
valence electron | an electron found on the outermost shell of an atom |
groups | the vertical columns on the periodic table |
period | the horizontal rows on the periodic table |
covalent bond | when two nonmetals react, atoms share electrons |
ionic bond | when a metal element reacts with a non-metal element, their atoms gain and lose electrons |
ion | an atom carries a positive or negative charge |
isotopes | atoms of the same element can differ in the number of neutrons |