MAT E202 Lecture Notes - Lecture 9: Chlorine, Covalent Bond, Electron Configuration
27 Jan 2017
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Atoms are arranged in unit cells (metal and ceramics) or molecules (polymers) which translate in 3d to form grain (crystals) The way grains are grouped together to form the bulk material. Weight based on the atomic mass unit (amu) defined as 1/12th the atomic mass of carbon-12 (6 protons, 6 neutrons) Consists of avogadro"s number of atoms or molecules. First 10 are described as 1s22s22p6 (quantum numbers) Chemical reactivity can be best understood by considering electron configurations and realizing elements are trying to achieve a filled outer shell. This represents a stable electron configuration like the inert gas. Lithium only has to lose one electron so it"s very reactive. Beryllium has to lose 2 electrons so it"s less reactive. The tendency to accept (attract) electron is expressed as electronegativity. Increases across a row to the right and up a column.
