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negatively charged particles in an atom


positively charged particles in an atom


neutrally charged particle in an atom

electron cloud

region surrounding the nucleus that contains the electrons

atomic number

the number of protons in the nucleus of each atom of that element


atoms of the same element that have different numbers of neutrons

mass number

the sum of the numbers of protons and neutrons in the nucleus of an atom

atomic mass

weighted average mass of all the isotopes of an element,


the positively charged dense center of an atom


an atom that has a negative or positive charge because it has gained or lost one or more electrons

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