The shortcuts for Windows 7. If you have not made the leap to Windows 8, this little cheat sheet will help you work more efficiently with Windows 7. Note: This list is part of Greg Shultz's comprehensive collection of Windows keyboard shortcuts, available as a PDF download. Also read: Free cheat sheet of 100 Windows 8 keyboard shortcuts.
i just ran across a problem asking me to identify the valence electrons on a sulfur atom in a sulfate ion. my understanding is that sulfate ion = 4 oxygen + 1 sulfur atom and has a 2- charge. now, in the answer to this question, it reads: sulfur in a sulfate ion has 12 valence electrons, its original six... *which i was able to find; 1s2,2s2,2p6,3s2,3p4 plus 6 more from the oxygens to which it is bonded.
We've used 6. And then around the outside atoms. So we have 6, 8, 10, and 24. We have two left over. We'll put them right here on the central atom. So we've used all 26 valence electrons. The structure looks pretty good. Each of the atoms has an octet. We've used the 26 valence electrons. So this is a possible structure for the sulfite ion, SO3 2-. Since Sulfur is in the third period on the periodic table, it can hold more than eight valence electrons. So we should check our formal charges here to see if this is the best structure. For the Sulfur, on the periodic table, it has 6 valence electrons. We have here, on the Lewis structure, 2 nonbonding; and then these right here are all involved in bonds, so 6 over 2. Six minus 2 minus 6 over 2 is a positive 1 for the central Sulfur. For the Oxygens; and they're all the same, so we'll just do one; on the periodic table, 6 valence electrons.