Talk about a beast of a concept in chemistry – chemical nomenclature. I mean just the concept itself sounds scary! And if it’s not taught smoothly, students will struggle with this for the rest of the school year. I find that when I teach chemical bonding as I’ll describe below, students learn nomenclature WITH EASE. Which I don’t say haphazardly. I really mean it! Here’s my tips for teaching chemical nomenclature.
Teach Ionic and Covalent Bonding Separately
I’ve done this both ways. Teach ionic and covalent bonding on the same day, and then splitting them into 2 different weeks. I’ll tell you, when I’ve taught ionic bonding first, then ionic nomenclature, then covalent bonding, then covalent nomenclature, it goes FAR better. It helps to keep the two totally separate. I also like to have a quiz after learning ionic bonding. This helps to ensure that the students have a good handle on things before moving into covalent bonding.
Teach Ionic Piecemeal: Binary, Polys and Transition Metals
When I teach ionic bonding I make sure to spread out everything over at least a week. First I use the classical sodium + chlorine in order to get the full valence shell concept down. Then we look at pairs of atoms and look at how many electrons would be needed to transfer to stabilize both atoms into ions.
On Day 2 I teach them the criss cross rule. They sort of love it because the first day of counting all the electrons and trying to rearrange them is a lot of work!
Day 3 I teach them about transition metals. The “weird” metals that can rearrange their interior electrons to change how many valence electrons they have. We do some criss-crossing with those too. Mostly uncriss crossing though, because I want to prepare them for naming which will come up later.
On Day 4 students learn about polyatomic ions – bundles of atoms that work together and carry a charge. They have their own names that we won’t spend time memorizing. Because that’s just a silly use of brain power. We’re also careful to note that when criss-crossing, the charge has to go ALL THE WAY ACROSS the bundle. This helps to protect those subscripts!
Finally on Day 5 is when they learn how to name ionic compounds. I teach them how to name the compounds in the same order that we learned them. Binary, transition metals and then polys. Really nothing out of the ordinary there. We use a graphic organizer to help navigate how to name ionic compounds.
Pause to Quiz on Ionic Before Going to Covalent
Then we take a day to sort of review ionic bonding and practice. And we’ll finish off ionic bonding with a midpoint quiz. I like to make sure that my students have a decent grip on ionic bonding before we get into covalent bonding. They spent a week REALLY loading up their brains with a lot of knowledge. I don’t want them to have to hold it all in until we get to the unit test.
Covalent is Counting
Then when we finally get to covalent bonding, things move a lot quicker. That’s because they’re already aware of the need for atoms to bond.
We look at covalent bonding as a compromise. The nonmetal atoms would prefer to gain their electrons, but there appears to be no metals around to get them from. So instead two nonmetal atoms will compromise and share their electrons. (Metals sort of do the same thing in a voltaic cell but we won’t talk about that until much later.)
In this lesson, students learn the properties of molecular compounds and spend a lot of time distinguishing ionic and covalent bonds.
For the second day of covalent bonding we mostly are counting atoms because that’s how I frame covalent naming. “Covalent is Counting.” With that floating in the back of mind, it’s a lot easier for students to distinguish ionic and covalent compounds.
If there’s prefixes it’s covalent. If it’s covalent, just count the atoms!
Use Graphic Organizers to Train Students
I’ve been using this ionic naming flowchart for YEARS and have now added the covalent piece! You can get it for free here. Also, make sure to read how I use graphic organizers in my chemistry class here!
You can get the full chemical bonding guided notes unit here.
