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Chapter 17 Vocab.
Vocab.
| 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 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. |