Students need to understand not only what the different properties of elements are, but also how those properties help to organize the periodic table to support their success with the two Performance Expectations (PEs) HS-PS1-1 and HS-PS1-2. HS-PS1-1 asks students to be able to predict element properties based on electron structure and element position on the periodic table. HS-PS1-2 asks students to explain simple chemical reactions based on valence electrons and periodic table trends. Students are far more successful in understanding both of these PEs with a foundation in understanding elemental families.
In order for students to "discover" (with guidance, of course) the different crucial properties that determine how elements are grouped and organized on the periodic table, I give each student an element identity. Students then go through a process of comparing and contrasting their elements with other students in class. As they do so, the differences and similarities should become apparent and students use the information on their individual element cards to begin developing a way to "group" similar elements.
Finally, students will compare their element with the rest of the classes' elements to group into "families" of their own creation.
While I take attendance, students do a warm-up activity in their composition Warm-Up/Reflection books. I use this warm-up to probe for students' prior knowledge about the day's upcoming lesson. (To read more about Warm Up and Reflection Books please see the attached resources.) For this particular lesson, my intention is to be as open-ended as possible.
Today's Warm-Up: "How do you sort things?"
In this case, the warm-up is asking students to apply prior knowledge and prepares them for today's activity during which they are expected to compare and contrast different elements.
If time permits, I walk around with a self-inking stamp to stamp the completed warm-ups indicating participation, but not necessarily accuracy. On days when there is too much business keeping, I do not stamp. Students have been told that warm-ups are occasionally immediately checked and other times not. At the end of each unit, Warm-Up/Reflection Books are collected and spot-checked.
Today, I do not stamp--instead I ask students to share out answers. As students share out, I list on the white board their answers. Some common answers include:
I leave the answers on the board to prompt continued thinking about what other possible answers might be while students embark on the day's activity.
As I walk around to stamp student warm-ups, I hand out pre-cut cards of elements. The element cards can be found here: Element Groups Properties Cards. Depending on the level of my students, I might print out the cards on different colored cardstock (one color per different page in the file--there are seven pages). If my students are an honors class or high level performers, I use the same color for everybody. If not, I print out each page on a different color paper or cardstock to serve as a not-so-subtle visual hint for how to finally sort the elements into families.
Once every student has an element card, I ask students to read the card and tell me what types of things are listed on the card. I expect students to notice that these things are included:
I direct students to take out a clean sheet of paper and put the appropriate heading at the top. I tell students to write their element at the top as a title. Then, I show students how to make a T-chart on their papers (I use a whiteboard, but a document camera and projector could also be used.). The table should have as two column headings "Similarities" and "Differences."
I tell students to pair up. If there is an odd number of students, I let one trio exist instead of a pair. Students should list the element of their partner at the top of the T-chart. They will have 3 minutes to find similarities and differences between the elements. And then they will need to find a new partner and repeat the comparing/contrasting twice.
At the end of 10 minutes, students should have completed 3 different T-charts on their papers.
Now that students have had a chance to compare and contrast their elements with three others, students should have a better idea about how to compare and contrast elements when trying to group like elements together.
I instruct students to think about how we might sort elements. I ask students:
Every student will need to find a "family." I will encourage students to get up and move around before settling in at a lab station with their determined family. If students are having difficulty finding the proper family, I might ask some of the following questions to get students on the right track:
Once students feel they have found their elemental families, I will ask students to answer the following questions on a piece of chart paper (by writing the questions on the whiteboard):
Students will share out their answers to the entire class, presenting as a group using the chart paper.
Key learning that needs to take place is:
I ask the following questions as we are discussing the chart papers to ensure students are making those critical connections:
In student's Warm-Up/Reflection Books, students should spend about 3-5 minutes writing a response to the day's reflection prompt. Prompts are designed to either help students focus on key learning goals from the day's lesson or to prompt deeper thinking. The responses also allow me to see if there are any students who are missing the mark in terms of understanding. The collection of responses in the composition books can also show a progression (or lack thereof) for individual students. (For more information about how I use Warm Up and Reflection Books, please see the attached resource.)
Today's Reflection Prompt: "What determines whether or not an element belongs to a certain family?"
Desired student responses should indicate that: