CHE 1110 Lecture Notes - Lecture 1: Alkali Metal, Nonmetal, Scientific Method
18 Sep 2018
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The vertical lines are the group of family , also designated by the top element. Post transition elements, neither metal or nonmetal, semimetals. Metal: metallic luster, malleability, ductility, conduct electricity, mostly solids at room t. Nonmetals: dull, not malleable, not ductile, poor conductors. The characteristics of metalloids midway between metals and non metals is out first encounter with trends in the periodic table. Metallic/nonmetallic properties change gradually across and down the periodic table; there are few abrupt changes. Atoms bind together to form compounds which may be molecular (discrete uncharged entities), or ionic (collections of electrically charged atoms) Molecules have three-dimensional structure: we represent atoms as spheres or circles with conventional colors and proportional sizes. We also represent chemical substances with chemical formulas: A free element: the chemical symbol from the periodic table. A diatomic molecule: a molecule composed of two atoms, using subscripts to devote numbers of atoms: h2, o2, n2, cl2, never superscripts.
