If you’re a high school chemistry teacher, chances are you’ve leaned on lecturing, notes, rote memorization, and drill practice using octet rule worksheets to teach the octet rule concept and reinforce its implications. While repetition is undoubtedly effective – practice, indeed, makes progress – once concepts are learned, these approaches don’t develop the reasoning and problem-solving abilities that students need to excel in high school chemistry. The NGSS cross-cutting concepts, when strategically planned for as integral elements of inquiry-based science activities, make for meaningful moments that create lasting learning of complex foundational concepts like the octet rule.
Real reasoning comes from modeling, active exploration, and evidence from either or both. These are all core expectations laid out within the Next Generation Science Standards. It’s often difficult, though, for high school science teachers to break free from the conventional plan of “lecture with lab” and stretch toward planning with the NGSS cross-cutting concepts in mind. They believe that students who can’t or don’t complete octet rule worksheets with accuracy aren’t being responsible for their learning.
That’s why, in this post, I’m sharing specifically how and where all seven of the NGSS cross-cutting concepts show up in a single representative lesson plan for teaching the octet rule and how this approach not only engages students in active, inquiry-based learning but also ensures they walk away with a deep understanding of the science at hand.
What Are NGSS Cross-Cutting Concepts?
The NGSS identifies seven cross-cutting concepts in science that help students make connections across science disciplines that can’t possibly be communicated through the use of simple octet rule worksheets:
- Cause and Effect
- Patterns
- Stability and Change
- Scale, Proportion, and Quantity
- Structure and Function
- Energy and Matter
- Systems and System Models
Each of these concepts is evident and must be considered or used by students in this inquiry-based activity for teaching the octet rule:
Read on for some perspective on how these ideas come to life when I’m leading this lesson in my classroom and how it might compare to the rote memorization and drill practice required by students to complete simple octet rule worksheets. For a detailed breakdown of the framework for the complete lesson – including a warmup, clear lesson goals, data analysis, and skill practice, bookmark the complete lesson analysis to read later or watch on YouTube!
The NGSS Cross-Cutting Concepts Applied
1. Cause and Effect
This concept explores the relationships between events or phenomena, highlighting how certain factors or actions can cause specific outcomes. Understanding cause-and-effect relationships helps scientists make predictions, analyze data, and explain phenomena.
Students must consider WHY electrons ionize or bond: without a full octet of valence electrons, atoms are unstable. In this context, students identify any atomic model with less than eight valence electrons as one which has cause to undergo the effect that is chemical change to achieve stability. To demonstrate their understanding of this cause and effect cross-cutting concept, students adjust Bohr model diagrams, orbital diagrams, and electron configurations.
To extend the cause and effect idea into student learning outcomes, the inquiry-based actions required by students in this activity produces the effect of them being able to observe how changes to the outermost electrons in each and every model produces models that resemble noble gases.
2. Patterns
Patterns refer to the recurring and predictable similarities or regularities that can be observed in the natural and designed world. Identifying and understanding patterns is crucial for making predictions, analyzing data, and developing scientific models.
Patterns are the primary cross-cutting concept named by the NGSS to be included with instruction on the related standard, HS-PS1-1., which reads as follows:
Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
When students develop and use the Bohr models, orbital diagrams, and electron configurations to consider how the cause and effect of the octet rule is applied, they also uncover the following periodic table patterns from the evidence they create:
Metals lose electrons to achieve stability.
- The orbitals and electrons within their atomic models appear the same as those of the noble gases in the previous period.
Nonmetals gain electrons to complete their octet.
- The orbitals and electrons within their atomic models appear the same as those of the noble gases in the same period.
Noble gases remain stable without changes.
To consider how the design of this inquiry-based activity produces an artifact that allows students to argue reasoning from evidence, take some time to study the complete lesson analysis.
3. Stability and Change
Stability refers to the state of equilibrium or balance within a system, while change refers to the process of alteration or transformation. This concept explores the factors that affect stability and the causes and effects of changes in systems over time.
The ultimate goal of the octet rule for atoms is, of course, achieving stability as it relates to the propensity for chemical change.
Students apply their understanding by adjusting atomic models; those with eight valence electrons don’t change, while those that don’t have eight valence electrons will gain or lose electrons accordingly.
Especially when confronted with atomic models of lithium, beryllium, and boron – the exceptions to the octet rule which require only two valence electrons rather than eight – students are challenged to think through what stability truly means, how it is portrayed, and how it is achieved.
This is the clear advantage to choosing to design lessons and learning activities around the NGSS cross-cutting concepts.
4. Scale, Proportion, and Quantity
Scale refers to the size or magnitude of an object or phenomenon, while proportion refers to the relative sizes or quantities of different elements. This concept helps students understand how things are related in size or quantity and how changes in scale can impact relationships and properties.
Since “eight is great” is the echoing theme of the octet rule, as long as we’re ensuring that students are working with and applying this concept of “making eight”, this NGSS cross-cutting concept is being addressed.
Notably, though, in this activity, students must think about how an octet will be achieved. After all, every atom that doesn’t have eight valence electrons has less than eight valence electrons. Yet, some will gain electrons and some will lose electrons. In this way, the scale, proportion, and quantity cross-cutting concept is extended to also apply to the energy and matter cross-cutting concept that we’ll discuss shortly. There is, in fact, an energetically-favorable process for achieving the octet. By challenging students to develop models with sound reasoning (an NGSS science and engineering practice), we are reinforcing another science and engineering practice related to using math and computational thinking.
When NGSS cross-cutting concepts are considered first and foremost as the means through which students will uncover core ideas related to the content, the NGSS science and engineering practices are naturally employed and alignment with the standards are satisfied!
5. Structure and Function
This concept involves examining the relationship between the structure of an object or system and its function or purpose. Understanding the connections between structure and function helps scientists analyze and explain the characteristics and behaviors of different phenomena.
Chemistry teachers know that the reactivity of an element directly correlates to its atomic structure, and this is exactly what our students need to learn! While we can teach this through “show and tell”, actively engaging with the models themselves equips students with the tools they’ll be able to use in subsequent problem-solving as they are charged with applying periodic patterns to scenarios related to chemical bonding and chemical reactions.
While this lesson design focuses on the formation of ions through the gain or loss of electrons, the octet rule is the foundation upon which we will teach students is the driving force for all bonding including covalent bonding and metallic bonding which reflect sharing electrons rather than transferring them.
6. Energy and Matter
Energy and matter are fundamental concepts in science. This cross-cutting concept focuses on understanding the flow and transformation of energy and matter within systems. It explores how energy is transferred, converted, and conserved, as well as the properties and behavior of matter.
This NGSS cross-cutting concept might arguably be a stretch when it comes to its integration in this activity. However, as mentioned previously in this article, students are unable to make educated guesses as to how the valence orbital of atoms will change to achieve octets unless they consider which conditions would be most energetically-favorable.
Though most inquiry-based, active learning requires little to no lecture, this notion of energetic-favorability must be introduced prior to having students work with this activity. In my classroom, I simplify this abstract concept by simply sharing that nature wants to expend the least energy possible. Teenagers can easily relate to this idea! Whether we frame it in terms of physical work – like doing household chores – or mental work – like doing homework and taking tests, students all agree that less is best!
For this to work, students also really need to realize that the gain or loss of electrons happens one-by-one. So, if students are deciding between gaining seven electrons or losing one electron, they realize that one electron would be one event and, therefore, require much less energy than gaining seven electrons over seven unique events.
7. Systems and System Models
Systems are collections of interacting parts or components that work together to perform a function or produce an outcome. This concept emphasizes the understanding of systems, their components, and the interactions between them. It also involves the use of models to represent and analyze systems.
This NGSS cross-cutting concept is another one that is inherent to the core idea being considered.
Though electrons’ location, behavior, and energy creates the physical and chemical properties we observe in all substance, each one exists as part of a larger system, functioning within that system and among other atomic systems. In working through the octet rule activity using the models provided here, students observe, evaluate, and consider how each electron contributes to an atom’s overall stability and, in the future, each electron will impact the stability of whole compounds.
Need a Quick Reference Tool When Planning For
The NGSS Cross-Cutting Concepts?
The Cross-Cutting Concepts Cheat Sheet is an example of one of the many resources members enjoy in The Digital Instructional Design Studio, my PD program designed to help teachers build a student-centered system for teaching inquiry-based science.
This tool provides succinct definitions and planning prompts for each NGSS cross-cutting concept and can even be shared with students to help condition their awareness of how these features are characteristic across all science concepts and courses.
How Integrating NGSS Cross-Cutting Concepts Will Outperform Your Octet Rule Worksheets
Traditional octet rule worksheets often emphasize other core ideas like predicting ion charge or drawing Lewis structure. While these tasks do represent ideas and skills related to the HS-PS1-1. standard, they rely more heavily on the knowledge and use of periodic table patterns than the development and use of models as evidence to support those patterns.
By emphasizing the NGSS cross-cutting concepts, this octet rule lesson transforms learning into an active, inquiry-driven process where the following tenets of true learning are observed:
INCREASED Student Engagement
Students can work independently or collaboratively to analyze and adjust models. Where collaborative learning structures are encouraged, students are able to learn from one another through meaningful questioning, proposing, and discussing alternatives. Such exchange is representative of what happens in real science labs around the world.
Students can collaborate to complete octet rule worksheets, but nothing about the format reads ‘experimentation’, ‘exploration’, or ‘consideration’. Instead, students are likely to be driven only by recording the right answers, leaning on the high achievers within a group to lead the charge.
Rational Reasoning Skills
The nature of the activity requires students to think through their observations and use them as evidence to argue the reason for the choices they made. If and when they can’t produce that argument, we are better able to know when intervention is necessary and, perhaps, more one-on-one attention is needed in our delivery.
When we assign octet rule worksheets, we never really know if the responses students produce are even authentic let alone insightful with regard to student understanding and progress.
Real-World Connections
Critical-thinking and good decision-making comes from the practice and learned ability to consider all relevant information, consider all sources, hypothesize, test its truth, discuss it with other privy parties, and make sound conclusions.
Octet rule worksheets condition memory, not meaning.
When the NGSS cross-cutting concepts are applied in our science lessons with integrity and consistency, I believe we’re better able to prepare our students to work through challenges and circumstances they’ll encounter in the real world.
This analysis is just a commentary on the inquiry-based activity central to this lesson. There are other equally as critical elements to a lesson plan that make or break it as an effective tool for learning in the classroom. Be sure to check out and consider the complete lesson analysis here.
Include More NGSS Cross-Cutting Concepts In Your Secondary Science Lesson Plans
Are you a chemistry teacher ready to replace your octet rule worksheets with a more 3-dimensional alternative?
You can explore a detailed analysis of the full octet rule lesson and purchase it from my Teachers Pay Teachers store.
Maybe you’re ready to replace more than just your octet rule worksheets and practice more 3-dimensional learning by applying the NGSS cross-cutting concepts with more consistency …
If so, download five free lessons to get an even better idea of how my year-long chemistry curriculum, micro2MACRO, might be able to transform your chemistry classroom into one full of inquiry and intrigue!
You don’t teach chemistry? Never used octet rule worksheets? That’s okay! I’ve got you covered, too!
Consider joining The Digital Instructional Design Studio, where you’ll gain access to resources like the Cross-Cutting Concepts Cheat Sheet to make planning student-centered, inquiry-based, NGSS-aligned active learning easier and more effective.
