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Chap. 17
Term | Definition |
---|---|
atom | the smallest particle of an element that still remains the properties of the element |
nucleus | positively charged center of an atom that contains protons and neutrons and is surrounded by a cloud of electrons |
proton | particle, composed of quarks, inside the nucleus of an atom that has a charge of 1+ |
neutron | neutral particle, composed of quarks, inside the nucleus of an atom |
electron | particles surrounding the center of an atom that have a charge of 1- |
quark | particles of matter that make up protons and neutrons |
electron cloud | area around the nucleus of an atom where the atom's electrons are most likely to be found |
atomic number | number of protons in an atom's nucleus |
mass number | sum of the number of protons and neutrons in an atom's nucleus |
isotope | atoms of the same element that have different numbers of neutrons |
average atomic mass | weighted-average mass of the mixture of an element's isotopes |
periodic table | organized list of all known elements that are arranged by increasing atomic number and by changes in chemical and physical properties |
group | vertical column in the periodic table |
electron dot diagram | uses the symbol for an element and dots representing the number of electrons in the element's outer energy level |
period | horizontal row in the periodic table; the amount of time it takes one wavelength to pass a fixed point; is expressed in seconds |