CHEM 2070 Chapter Notes - Chapter 2: Bunsen Burner, Diatomic Molecule, Atomic Mass
26 Aug 2016
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Document Summary
Element any substance that cannot be broken down into simpler substances: modern definition: a substance that consists only of atoms with the same nuclear charge. 120 known elements (99. 99% of substances are made from 40) H more than 90% of atoms & 75% of observable mass: metals (75%) Characteristic luster, cast into shapes, conductors of heat and elec. All except mercury are (s) at room temperature (20 c: nonmetals. Others are (s) except for bromine (l) Diatomic molecules that have a subscript 2 (h,o,n,f,cl,br,i) Two or more atoms that are joined together. Diatomic molecule: consisting of just two atoms same or different. Compound a substance that can be broken down into two or more elements. Solids (s: fixed volume and fixed shape. Particles are held together in a rigid, well-defined lattice: not all are hard or rigid ex. gold. Liquids (l: fixed volume, but no specific shape. Held together, but particles are free to move within volume of liquid.
