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Unformatted text preview: ns are a dash non bonding or lone pairs are pairs of electrons are a pair of dots atom is the elemental symbol Rules for predic?ng Lewis Structures 1.
10. 11. 12.
13. Hydrogen atoms form only single bonds; they are always at the ends of a sequence of atoms. Hydrogen o\en is bonded to carbon, nitrogen or oxygen. Oxygen atoms usually do not bond to each other, except for O2, O3, superoxides and peroxides. Poly atomic molecules and ions o\en consist of a central atom (which is o\en listed ﬁrst in the chemical formula) surrounded by terminal atoms. There is o\en ?mes symmetry in the Lewis structure. To determine the total number of shared (bonding) and unshared (non‐bonding) electrons in a compound use the following rule: S= N‐A, where S is the total number of shared electrons, N is the total number of valence shell electrons needed by all the atom sin the molecule or ion to achieve noble gas conﬁgura?ons and A in the number of electron available in the valence shells of all the representa?ve atoms. If the structure is an anion add electrons for nega?ve, if it’s a ca?on subtract electron for each posi?ve charge. Write the skeletal structure, and connect bonded pairs of atoms by a dash. Each dash represents a shared pair of electrons. Place electrons about outer atoms so that each (except hydrogen) has an octet. Check that all atoms have sa?sﬁed the octet rule and that all the available electrons have been assigned. If the central atom has...
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