4 Bonding and Energy Transfer
4.2 Formal Charge
4.3 Your Line Structure "Kit"
4.8 Greenhouse Gases
4.9 Ozone Layer
So non-metals have a great many ways they can share electrons and satisfy the octet rule. You can end up with single, double, or even triple bonds when sharing to hit that perfect noble gas configuration. Below is a set of "here is what they look like" symbols and lines of many non-metals when inside a covalent molecular compound.
Ah yes, carbon has 4 valence electrons and will need another 4. This means there will be 4 bonding pairs of electrons around carbon in a typical neutral compound. That means 4 lines around carbon. Those four lines have four ways they can show up.
Having 5 valence electrons means that nitrogen only needs 3 more electrons and that means 3 bonding pairs and 1 lone pair.
Having 6 valence electrons means that oxygen only needs 2 more electrons and that means 2 bonding pairs and 2 lone pairs.
Hydrogen only needs 1 electron to match up with helium - its full "octet" is just 2 electrons. The halogens all have 7 electrons and also only need 1 electron to reach a full octet. This means the halogens are typically just 1 bonding pair and 3 lone pairs.
All of the templates on this page are assuming you've got a structure where is it possible to have all formal charges (see next section) equal to zero for all the elements listed here. Do realize that sometimes you MUST rearrange things and violate these best case scenario templates and have a +1 or –1 for formal charge. When you do this, there ARE other possibilities (see below). Those listed above should be your first try though.
Below are the most common versions of +1 and –1 formal charges for nitrogen and oxygen in typical organic compounds. Only resort to this when you have to and cannot make the zero formal charge versions work.
Even more rare is the case when carbon goes to +1 (carbocations) and –1 (carbanions) in compounds. These might come into play in reaction mechanisms (chapter 8). For most all stable organic compounds, you'll want to avoid these ions below. If you do use them, know that the species you're depicting is probably unstable and highly reactive.