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Unformatted text preview: valence electrons. Note:
For ions, the charge must be included in this by adding the charge on an anion or subtracting the charge on a
Calculate the Share d Pairs (SP) = the number of electrons to be shared in bonds. The SP is 1/2(ER - VE); for
CHO2-, this would be 1/2(26 - 18) = 4 shared pairs or four bonds.
Calculate the Lone Pairs (LP) = the number of electron pairs belonging to only one atom. The LP is 1/2(VE (2 × SP)); for CHO2-, this would be 1/2(18 - (2 × 4)) = 5 lone pairs. Notice that VE = 2 × (SP + LP).
Place the first atom in the molecular formula as the central atom, surrounded by the other atoms in the
compound. Figure 1
Draw bonds (shared pairs) from the central atom to each surrounding atom. The bonds are represented as lines;
each line represents two electrons. The number of lines should be equal to the number of shared pairs calculated
in step 3, which in this case is four. Since hydrogen follows the duet rule, it only prefers one bond. The fourth
bond can be drawn to either...
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This document was uploaded on 01/22/2014.
- Spring '14