Atoms, Law of Conservation of mass & proportions, counting atoms related terms
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| 418116146 | law of conservation of mass | states that mass is neither created nor destroyed during ordinary reactions or physical changes | |
| 418116147 | 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; textbook: if two or more different compounds are composed of the same two elements with a certain mass of the first element is always a ratio of small whole numbers | |
| 418116148 | law of definite proportions | The fact that a chemical compounds contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound | |
| 418116149 | atom | the smallest particle of an element that retains the chemical properties of that element | |
| 418116150 | nucleus | is a very small region located at the center of an atom | |
| 418116151 | proton | positively charged particles in the nucleus | |
| 418116152 | neutrons | neutral particles | |
| 418116153 | electrons | negatively charged particles in electron cloud region outside of nucleus | |
| 418116154 | electrons, neutrons, protons | Name the three subatomic particles in alphabetical order. | |
| 418116155 | cathode ray tube | Experiments in which electric current was passed through a glass tube filled with various gases at low pressures along with magnetic metal plates that helped discover the electron by Thomson and others. | |
| 418116156 | plum pudding models | Thomson's model for the atom in which the plums represented the electrons spread through the atom - prior to knowledge of nucleus (Today think of chocolate chip ice cream where chips are the electrons through out the atom.) | |
| 418116157 | alpha particles | positively charged particles with about four times the mass of a hydrogen atom used in Rutherford's Gold Foil Experiment which helped discover protons and nucleus of atom with the assistance of Marsden & Geiger. | |
| 418116158 | nuclear forces | holds the nuclear particles together (short range proton-neutron, proton-proton, and neutron-neutron) | |
| 418116159 | atomic number | the number of protons in the nucleus of each atom of an element | |
| 418116160 | isotopes | atoms of the same element that have different masses due to varying number of neutrons | |
| 418116161 | Protium | the most common type of hydrogen which has 1 proton and no neutrons | |
| 418116162 | deuterium | .015% of the earth's hydrogen atoms which has 1 proton and 1 neutron | |
| 418116163 | tritium | radioactive hydrogen which contains 1 proton and 2 neutrons | |
| 418116164 | mass number | total number of protons and neutrons in the nucleus of an isotope | |
| 418116165 | hyphen notation | the mass number is written with a hyphen after the name of the element | |
| 418116166 | nuclear symbol | shows the composition of a nucleus | |
| 418116167 | Nuclide | is a general term for a specific isotope of an element | |
| 418116168 | atomic mass unit | 1 amu, or is exactly 1/12 the mass of a carbon-12 atom | |
| 418116169 | average atomic mass | the weighted average of the atomic masses of the naturally occurring isotopes of an element | |
| 418116170 | Avogadro's number | 6.0221415 x 10^23 is the number of particles in exactly one mole of a pure substance | |
| 418116171 | Mole | is the amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12 | |
| 418116172 | molar mass | the mass of one mole of a pure substance | |
| 418116173 | artificial isotopes | isotopes made in a lab |
