| Term | Definition |
|---|
| Law of Conservation of Mass | states that mass is neither destroyed nor created during ordinary chemical reactions or physical changes |
| Law of definite proportions | a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound |
| Law of multiple proportions | if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers |
| atom | the smallest particle of an element that retains the chemical properties of that element |
| chemical reaction | the transformation of a substance or substances into one or more new substances |
| subatomic particles | protons (positive charge), neutrons (neutral charge), and electrons (negative charge) |
| alpha particles | positively charged particles with about 4 times the mass of a hydrogen atom |
| atomic number | the number of protons in the nucleus of each atom of that element. identifies an element |
| isotopes | atoms of the same element with different masses. have same number of protons and electrons but different numbers of neutrons |
| mass number | protons + neutrons |
| nuclear symbol | superscript= mass number, subscript= atomic number |
| mole | the amount of a substance that contains as many particles as there are atoms in exactly 12g of carbon-12 |
| atomic mass | in upper right-hand corner on the periodic table |
| proton | positive electric charge, mass 1.67 x 10^-24g, relative mass 1 amu |
| electron | negative electrical charge, mass 9.1 x 10^-28g, relative mass 0.0005 amu |
| neutron | no electric charge, mass 1.67 x 10^-24g, relative mass 1 amu |
| atomic mass unit | 1/12 weight of carbon-12, a standard mass for measuring atoms |
| avogadro's number | the number of particles in exactly 1 mole of pure substance |
| nuclide | a general term for any isotope of any element |
Combine with other sets
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