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Unformatted text preview: one of the oxygen atoms. Figure 2
Draw lone pairs on each of the non- hydrogen atoms. A lone pair is represented as two dots; each dot represents
an electron. Each non- hydrogen atom prefers eight electrons in the vicinity of the atom. If an atom has 1 bond, it
requires 3 lone pairs. If an atom has 2 bonds, it requires 2 lone pairs. If an atom has 3 bonds, it requires 1 lone
pair. If an atom has 4 bonds, do not add any additional lone pairs. In our example, C requires no lone pairs, one
oxygen requires 3 lone pairs and one oxygen requires 2 lone pairs. www.webassig n.net/ebooks/wsug encheml1/lab_6/manual.html 2/8 4/15/13 Lab 6 - M olecular Geometr y Figure 3
Calculate the formal charge (FC) on each atom. For an atom:
FC = VE − SP − (2 x LP)
where SP is the number of shared pairs on the atom and LP is the number of lone pairs on the atom. For
molecules the sum of the formal charges of all the atoms must be zero; for an ion, the sum will be the ionic
charge. To choose the more favorable of two Lewis structures, the one with the lowest FC on each individual
atom would be th...
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- Spring '14