Have you heard someone explain polar molecules and not understood it? Yeah, sure, you understand the polar molecule part. But polar in the context of nonpolar starts to get more fuzzy. Then you look at an example problem, and you think, "Well I know that is nonpolar, but I can't tell specifically why, but my gut says 'Nonpolar!'".
Let me explain how I teach this to my students and how I think you should explain it to your students for very easy understanding.
What is Polar?
There are two ways you can talk about polar molecules with your students: through “poles” or through electronegativity.
Most teachers will choose to use the “poles” explanation for beginner chemistry students or college prep courses. For more advanced chemistry students taking honors, AP, or IB chemistry, teachers will probably choose to use the electronegativity explanation.
Both are valid explanations, but the electronegativity explanation is a deeper explanation that allows for more understanding, but can be overwhelming for beginning chemistry students.
When introducing polarity through poles explain that there is one positive end and one negative end. Most teachers start out by drawing out a water molecule because it is very familiar to students. On the oxygen, draw out the electrons and put a minus sign to indicate that it has a partial negative charge. On the hydrogens, put a plus sign to indicate that they have partial positive charges.
It is that "polar opposite", where there is one end positive and one end negative that makes a molecule polar.
What is Nonpolar?
A nonpolar molecule is a molecule that doesn't have two distinct charge sites.
However, when you talk about this through the lens of electronegativity, you can see that there is some difference in charge throughout the molecule, but it is very small. That’s when many teachers use an electronegativity chart to determine degree of polarity.
Again, many teachers only discuss the electronegativty portion of this topic with their more advanced chemistry students.
Stop Saying "Cancel Out"
The one thing you can do to increase student understanding, is to stop saying "cancel out". When the phrase "cancel out" is used, the image that comes to mind is a left to right cancellation, or a top to bottom cancellation. But, often your students are thinking of the actual shapes of these molecules and it is hard to understand caddy-corner charges canceling each other out.
Instead, simply explain to students that a polar molecules have one single positive end and one single negative end. Anything different should be labeled as nonpolar at the most basic level. Of course, if your students are more advanced, or mathematically inclined, have them use the electronegativity chart.
You may have been handed a textbook, curriculum, or nothing. They said, “You have a science background, right? We need you to teach chemistry”. So, you taught it.
Then, you came across some person who asked you how you taught or how you felt about atoms first versus traditional chemistry. And you sidetracked the question until you could get on Google and stumble on this article.
So here is the low down on atoms first.
It Starts Similar to Traditional
Both the traditional and atoms first approach to teaching begin by teaching some form of measurement, SI units, classification of mater, and significant figures depending on state standards. The last thing taught with both approaches is elements and atoms. Usually, some discussion of protons, neutrons, and electrons happens.
Diverges after Protons, Neutrons, and Electrons
The atoms first approach believes at this point we’ve talked about protons, neutrons, and electrons, so why not take this opportunity to dive into the secret structure of the atom.
Depending on your state standards this may include Lewis dot structures, beta decay, alpha decay, and other nuclear chemistry topics. It may also include quantum numbers and electron configuration.
Begins Periodic Table
After covering the miniscule details of the behavior of the electrons, the atoms first approach goes on to teach the layout of the periodic table, ion formation, naming chemical compounds, writing chemical formulas, balancing chemical equations, and so on.
It boils down to tackling the unseen, deep chemistry earlier rather than later.
Atoms Come First
So, atoms come first in the atoms first approach. The point is to teach the minute intricacies of the atom before you teach even the periodic table.
In short, you dive deeeeep into chemistry going all the way into the secrets of the atom then you go back to surface level topics like the periodic table and how elements combine. Then the topics just keep building like traditional chemistry.
My question to you is, “Is it more important for your high school educated student to go into the workforce knowing how to write an electron configuration or to know what solvents would work best to get a stain out of their shirt?”
I’ll bet you teach your students the layout of the periodic table by having them color code the group names, right?
It is an effortless lesson to teach and grade. Students love it because they remember the content easier. But, why stop there?
There is so much more you can teach students through color coding the periodic table besides the alkali, alkaline, and transition metal groups?
Let me show you deep concepts that you can teach your students about chemistry buried in the periodic table. You can use color-coding to teach bonding principles, electron behavior, and many other foundational chemical principles.
The periodic table was laid out with careful consideration for trends, behaviors, and characteristics. Bring those properties to a vibrant, 3D life with these lessons.
Some of these lessons require specific colors. Others are open to your interpretation. Instruct your students to color-code however you see fit.
#1 Color Code to Learn the General Layout
Have students color alkali, alkaline, transition metals, halogens, nobel gases, metaloids, lanthanides, actinides, all different colors.
Make sure they color AND label the metals. I find that the remember more that way.
Pick up my fun periodic tables for free here to use with this lesson.
#2 Color Code to Learn Cations and Anions
In the CoScine Chemistry World, happy, positive things are sunshine yellow, and since protons are positive, they are obviously yellow.
The opposite is also true.
Sad things are blue, and since anions are negative, they are definitely blue.
Based on that color scheme, have your students color code a periodic table blue and yellow based on each element’s tendency to form a cation or anion.
The best part about this activity is that it subconsciously lays the foundation for writing chemical formulas correctly. For students, subconscious learning is the next best thing to learning by osmosis!
#3 Color Code to Learn Electron Configuration
Students get confused on what to write down for an electron configuration. Have them color code a periodic table for electron configuration and use it as a cheat sheet to simplify the process for them.
Color all checkpoints (aka. filled subshells like 1s2, 2p6, etc) checkered because it tells the students to keep reading the periodic table. Color all locations red because it means stop and write the complete electron configuration.
Color code an electron configuration sample so that students know how to use this electron configuration periodic table.
For example, in this picture we would have 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 5d10 6p3. The last space would be a location and it is colored red. The other spaces would be colored checkered.
#4 Color Code to Learn spdf Blocks
Have students color the s block, p block, d block, and f block. Anytime my students and I color, I also have them label as well. Explain to the students that the reason we color is to trigger memory recall later of the labels and information. We aren't coloring for the sake of coloring. That really helps them see the purpose of these activities.
For the orbitals, I have them draw the associated orbital shape, how many electrons each orbital can hold, and label each color with an orbital letter.
Just because you are coloring doesn't mean you can't raise the bar.
#5 Color Code to Learn Bonding
Once students have color coded metals, metalloids, and non metals, they can use the color coding system to quickly decide if a compound has an ionic or covalent bond(<---Great blog post on hacking this).
Have students draw a gray square next to a gray square and label it a metallic bond. A red square next to a gold square and label that a covalent bond. Draw two red squares and label it a covalent bond. Last, I have them draw a gray square next to a red square and write ionic bond.
They love to use this as a cheat sheet throughout the year.
#6 Color Code to Learn Periodic Trends
This one is really fun and very visual. Students pick one color per trend and color the periodic table according to that trend.
I like this because one corner will be very dark and the opposing corner much lighter. You can differentiate this and make it more challenging by requiring students to color in exceptions.
#7 Color Code to Learn Charges
When beginning to learn the periodic table, students need a visual reminder on which groups have which charge.
Here I've given positive and negative 1, the color red. Positive and negative 2, the color orange. Positive and negative 3, the color yellow. Positive and negative 4, the color green.
So as long as you have your students label the left side of the periodic table positive, and the right side negative, your students will be good to go.
Now that is a lot of periodic table coloring ideas! Try them out.
Imagine how much fun your students will have coloring the periodic table these different ways. Not only are these lessons very memorable, but they are very low prep and easy to assess. They will make learning these lessons so much easier for your students and we all know when learning is easy on students, it is easy on us teachers!
Plus, now your students will have a whole booklet of periodic table references they can use at any time.
Go sign up for my free resource library and get those periodic tables for free. Of course, these lessons work with any periodic table so feel free to use your own.
If your students just aren’t getting the more mathematical approach (aka, crossing charges), maybe try a different tactic.
Illustrate for them WHY we balance charges.
Everyone loves a good hack. Especially students and teachers. Imagine your student’s delight when you teach them these two shortcuts.
They will know that your purpose is to make learning chemistry easier on them.
Read on for the sanity saving tricks.
You can teach them through lecture and PowerPoint. But, maybe you want to mix it up? Maybe you want to put a little spice in your classroom? Maybe make the polyatomic ion list a little easier to memorize?
After all you gave them the list and asked them to learn it before the quiz-and then nothing happened.
Do I have a plan for you!
Yeah, sure. You can teach quantum chemistry like you always have. I did.
You can stand at the front of the classroom and explain about the location of an electron, how it is oriented in space, and the probability of finding it at a given time.
You can explain with no diagrams or some of the traditional, hard to understand diagrams.
You can say, "If you are in the s orbital there is only one option for l and also for ml. That should be obvious based on it being in the s orbital."
Or you could really break the topic down into tangible, bite size pieces for your students. You could make students SEE quantum chemistry easily. (#DoodleNotes are awesome for this)
Imagine quantum chemistry with bright colors, simplified instructions, and specific illustrations that inspire understanding.
Now, that sounds amazing!
Do your students look at you like you’re speaking gibberish when explaining a new topic in chemistry?
Do you get no response when you say, “Any questions?” at the end of class? If is your classroom some days, it’s time to grab your uninterested student’s attention.
It is so frustrating when you have spent 50 minutes explaining a topic and get crickets. I know.
You think, “Did I explain it right? Did they just not listen? Should I have done more practice problems?”
No, they are bored.
Have you thought about how far out of their world some topics in chemistry are? For some students, we might as well be explaining rocket science.
Rock their world by trying one of these fun tactics and see your students become sponges in your classroom.
Yes, you may have occasional rowdiness (especially with #7), but they will be engaged.
And that involvement is what we all dream of seeing in our classrooms.
When you teach molar mass, do you just throw up example problems? Or, is there a strategy behind the examples you choose?
There isn't a right way to teach students how to calculate molar mass, but there is definitely a wrong way! When you are choosing your examples, make sure that there is a reason behind that example.
Start with a simple example and then build ideas onto that example. Don't just jump in with a polyatomic ion containing compound and think that students will instantly understand molar mass if you just explain it really well. (Pssst....I did that!!!)
So, if you can't start with a polyatomic ion, what type of problem is good to start with?
Students don't know the basic "chemistry language" when they start the class.
When you teach biology or anatomy or physics student already have a basic working knowledge of plants, and bones, and gravity. But chemistry is built on a table that they don't know and a lot of concepts they've never heard of that they need to master fairly quickly. This is why I color code as much as I can.
Hi! I'm CoScine. I write chemistry worksheets for visual learners. They are fun, easy to follow, and most of them are quick to grade. Since I started my teaching career at the college level, these are just simple chemistry. These worksheets are hard core science.