Chapter 2 Notes
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dawnlwalker Plus on October 15, 2012
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things that might be important from chapter 2
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51 terms
English | Chemistry |
|---|---|
 Democritus and early Greek philosophers | thought the material would must be made of tiny invisible particles called atomos meaning "indivisible or uncuttable" |
| Isaac Newton | favored the idea of atoms |
| John Dalton | created Dalton's atomic theory |
| Dalton's atomic theory-1 | Each element is composed to extremely small particles called atoms |
| Dalton's atomic theory-2 | All atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of all other elements. |
| Dalton's atomic theory-3 | The atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions |
| Dalton's atomic theory-4 | Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms |
| atoms | smallest particles of an element that retain the chemical identity of the element |
| law of conservation of mass | The total mass of materials present after a chemical reaction is the same as the total mass present before the reaction. |
| law of multiple proportions | if two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers. |
| subatomic particles | the atom is composed of these smaller parts |
| particles with the same charge | repel one another |
| particles with unlike charges | attract one another |
| cathode rays | radiation produced from the negative electrode when high voltage was applied to partially excavated tubes |
| cathode | negative electrode |
| J. J. Thomson | observed cathode rays and discovered the electron, "plum-pudding model" |
| Robert Millikan | oil-drop experiment; discovered the mass of an electron |
| radioactivity | the spontaneous emission of radiation |
| Henri Becquerel | studying uranium and discovered it spontaneously emits radiation |
| Marie Curie | with husband began experiments to isolate radioactive components of uranium |
| Ernest Rutherford | revealed three types of radiation: alpha, beta, gamma; "gold foil experiment" |
| "plum-pudding model" | J. J. Thomson proposed that the atom was a uniform sphere with embedded electrons |
| protons | positively charged particles in the nucleus |
| neutrons | neutral particles in the nucleus |
| James Chadwick | discovered neutrons |
| electronic charge | 1.602 x 10⁻¹⁹ C; all charges of subatomic particles are represented as multiples of this charge |
| atomic mass unit | 1.66054 x 10⁻²⁴ g = 1 amu |
| angstrom | A°, 10⁻¹⁰ m |
| atomic number | the number of protons in any element (subscript) |
| number of electrons | same as number of protons |
| mass number | total number of protons plus neutrons in an atom (superscript) |
| isotopes | atoms with identical atomic numbers but different mass numbers |
| average atomic mass | found using masses of isotopes and relative abundance on earth |
| metallic elements or metals | left side and middle of periodic table |
| nonmetallic elements or nonmetals | separated from metals by a diagonal step ladder in the periodic table |
| metalloids | lie along the line between metals and nonmetals in the periodic table |
| molecule | assembly of two or more atoms tightly bound together |
| chemical formula | shows the elements in the compound and the ratio of atoms |
| diatomic molecule | made up of two atoms |
| molecular compounds | composed of molecules of more than one type of element |
| molecular formulas | actual numbers and types of atoms in a molecule |
| empirical formulas | lowest ratio of elements in a molecule |
| structural formula | shows which atoms are attached within a molecule |
| ion | a charged particle |
| anion | negatively charged particle |
| cation | positively charged particle |
| polyatomic ions | consist of atoms joined as in a molecule with a net charge |
| ionic compound | compound that contains both positively and negatively charged ions |
| chemical nomenclature | system for names and formulas of compounds |
| hydrocarbons | only contain carbon and hydrogen |
| alkanes | hydrocarbons that contain carbon atoms that are bonded to four other atoms |
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