How does the carbon atom complete its octet?

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anonymous · Answer

Do this: Look at this image and see if you can find where carbon should be. Pretend you're playing monopoly and rolled a four, count four over to the right. What element are you on now? Does that element have a full valence/outer shell octet? http://upload.wikimedia.org/wikipedia/commons/e/e5/Periodic_Table_structure.svg Neon is (which is what carbon's electron configuration looks like when it gets it's octet) 1s$^2$ 2s$^2$ 2p$^6$ Carbon is: 1s$^2$ 2s$^2$ 2p$^2$ See how it's 4 short? So it needs 4 more electrons to complete the octet. Check it: Neon: (2 s-orbitals) + (6 p-orbitals) = 8 electrons in the "2" level Carbon: (8 electrons for an octet) - ( (2 s-orbitals) + (2 p-orbitals) = missing 4 electrons in "2" level This "2" level is the outermost orbital level for these types of elements (in that row on the periodic table), which gives electrons in this region a special name: valence electrons. The valence electrons are almost always the ones involved with chemical reactions, so it's very important you understand this fundamental concept, which is made easy by visualizing it with the periodic table.