Term
| Law of Conservation of Mass |
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Definition
| a law stating that matter is neither created nor destroyed in a chemical reaction |
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| Law of Definite Proportions |
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Definition
| a law stating that all samples of a given compound have the same proportions of their constituent elements |
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| Law of Multiple Proportions |
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Definition
| a law stating that when two elements (A and B) form two different compounds, the masses of element B that combine with with one gram of element A can be expressed as a ratio of small whole numbers |
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Definition
| the theory that each element is composed of tiny indestructible particles called atoms, that all atoms of a given element have the same mass and other properties , and that atoms combine in simple, whole-number ratios to form compounds |
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| a stream of electrons produced when a high electrical voltage is applied between two electrodes within a partially evacuated tube |
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| a fundamental property of certain particles that causes them to experience a force in the presence of electric fields |
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| a negatively charged, low mass particle found outside the nucleus of all atoms that occupies most of the atom's volume but contributes almost none to its mass |
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| the emission of subatomic particles or high-energy electromagnetic radiation by the unstable nuclei of certain atoms |
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| the theory that most of the atom's mass and all of its positive charge is contained in a small, dense nucleus |
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Definition
| the very small, dense core of the atom that contains most of the atom's mass and all of its positive charge; it is composed of protons and neutrons |
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Definition
| an electrically neutral subatomic particle found in the nucleus of an atom, with a mass almost equal to that of a proton |
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Definition
| an positively charged subatomic particle found in the nucleus of the atom |
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Definition
| a unit used to express the masses of atoms and subatomic particles , defined as 1/12th the mass of a carbon atom containing six protons and six neutrons |
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Definition
| the number of protons in an atom; the atomic number defines the element |
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Definition
| a one- or two- letter abbreviation for an element that is listed directly below its atomic number on the periodic table |
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Definition
| atoms of the same element with the same number of protons but different numbers of neutrons and consequently different masses |
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| the relative percentage of a particular isotope in a naturally occurring sample with respect to other isotopes of the same element |
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Definition
| the sum of the number of protons and neutrons in an atom |
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Definition
| an atom or molecule with a net charge caused by the loss or gain of electrons |
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| a law based on the observation that when the elements are arranged in order of increasing mass, certain sets of properties recur periodically |
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Definition
| a large class of elements that are generally good conductors of heat and electricity, malleable, ductile, lustrous, and tend to lose electrons during chemical changes |
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Definition
| a class of elements that tend to be poor conductors of heat and electricity and usually gain electrons during chemical reactions |
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Definition
| a category of elements found on the boundary between the metals and nonmetals of the periodic table, with properties intermediate between those of both groups; also called semimetals |
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Definition
| a material with intermediate electrical conductivity that can be changed and controlled |
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| those elements found in the s or p blocks of the periodic table, whose properties tend to be predictable based on their position in the table |
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| Transition Elements (transition metals) |
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Definition
| those elements found in the d block of the periodic table whose properties tend to be less predictable based simply on their position in the table |
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Definition
| columns within the main group elements in the periodic table that contain elements that exhibit similar chemical properties |
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Definition
| the group 8A elements, which are largely unreactive (inert) due to their stable filled p orbitals |
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Definition
| highly reactive metals in group 1A of the periodic table |
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| fairly reactive metals in group 2A of the periodic table |
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Definition
| highly reactive nonmetals in group 7A of the periodic table |
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Definition
| the average mass in amu of the atoms of a particular element based on the relative abundance of the various isotopes; it is numerically equivalent to the mass in grams of one mole of the element |
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Definition
| an experimental method of determining the precise mass and relative abundance of isotopes in a given sample using an instrument called a mass spectrometer |
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Definition
| a unit defined as the amount of material containing 6.0221421 x 1023 (avogadro's number) particles. |
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Definition
| the number of 12C atoms in exactly 12 g of 12C; equal to 6.022 x 1023 |
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Definition
| the mass in grams of one mole of atoms of an element; numerically equivalent to the atomic mass of the element in amu |
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