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Chapter 17
Term | Definition |
---|---|
Atom | the smallest particle of an element that still retains 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 atoms 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 |