CHEM 110 Lecture Notes - Lecture 10: Ammonia, Unpaired Electron, Vsepr Theory
10 Mar 2017
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3. 4 - drawing lewis structures of molecules and polyatomic ions. Use chemical symbols for the various elements to write the skeletal structure of the compound. The least electronegative atom will be placed in the central position. Halogens occupy terminal positions, except when more electronegative elements are present. Carbon often forms chains of carbon-carbon covalent bonds. Determine the number of valence electrons associated with each atom in the compound. Combine these valence electrons to determine the total number of valence electrons in the compound. Polyatomic cations, subtract one electron for every positive charge. Polyatomic anions add one electron for every negative charge. Connect the central atom to each of the surrounding with single bonds. Next, complete octets of all the atoms bonded to the central atom. Electrons not involved in bonding are represented as lone pairs. After the terminal atoms have an octet, provide the central atom with an octet if valence electrons are still available.
