Submitted by Sheila Smith / University of Michigan- Dearborn on Tue, 09/13/2011 - 16:05
My Notes

I use this introductory exercise at the beginning (the very first thing) of my one semester topics course in Bioinorganic Chemistry and as the first exercise in my Bioinorganic unit in my senior level Inorganic Course.  The exercise is a very simple one, but generates a lot of great discussion, requiring students to access knowledge from prior chemistry and biology courses, as well s common knowledge from sources external to their academic career.  Students are often surprised to see how much they know before a topic is covered.  

 I distribute to each student a photocopied periodic table along with 3 different highlighter pens.  

I then ask the following three questions, giving the students 5 minutes for each.   Students are instructed to highlight only a section of each box (element).  

Q1.  Identify all the metals that are required in biological systems. 

Q2.  Identify all the metals that are toxic to biological systems.

Q3. Identify the metals that are used for medicinal purposes. 

Attachment Size
BioinorganicPTkey001.pdf 732.51 KB
Learning Goals

• A student should be able to identify (some) metals that are required in biological systems.

• A student should be able to identify (some) metals that are toxic to biological systems.

• A student should be able to identify (some) metals that are used for medicinal purposes.

• A student should be able to discuss the factors that determine whether a metal is toxic or not, including oxidation states, quantities, etc.

Equipment needs

Periodic Tables, highlighter pens

I use periodic tables created by Todd Helmenstine and maintained at

Implementation Notes
I use the three questions exactly as written above. I am very careful to make no reference to amounts, oxidation states, etc, since these are wonderful points that can be raised in the ensuing discussion, usually at the students' leading. After the students fill out the periodic tables, we discuss their answers to each of the three questions. No one student gets all the correct answers (I'm not even sure that I could get all the answers correct). The point is to show the students that they already have some basic knowledge of the field, and to get them thinking about the various roles that metals play in biological systems. I have attached a "key" with some teaching notes... this is not intended to be exhaustive. I just answered the questions off the top of my head. I'd love for people to add to the teaching notes as they use the exercise.
Time Required
15 minutes for the students to label tables, up to an hour for discussion


Evaluation Methods
This is an introductory in class activity. I usually collect the periodic tables to see what students were thinking, but the value of the exercise is in introducing the various roles of metals in biological systems.
Evaluation Results
Most students get the relevant alkali and alkaline earth metals along with Iron and zinc. Many cite the Centrum (or other vitamin/ mineral) bottle as their source of knowledge. I am always fascinated by the large percentage of the students who forget the inner transition metals altogether. Students are intrigued by how many metals end up having two or even three colors.
Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA
Chris Goldsmith / Auburn University

My one quibble would be that most of these metals would be toxic if present in a large enough concentration (this might be a good way of introducing the concept of homeostasis).

Aside from that, I think it's a good in-class exercise.


Christian R. Goldsmith Auburn University Department of Chemistry and Biochemistry

Thu, 10/06/2011 - 11:42 Permalink
Mwalimu / Russell Sage College

A senior member of my department came to my Adv. Inorganic class as I was covering Bioinorganic chemistry and LUCKILY i was using this LO.. I got really good reviews from him on class participation as my students were very excited and enjoyed the activity! Thanks!

Wed, 08/19/2015 - 15:26 Permalink
Cassie Lilly / NCSU

I have used this LO in my last two Inorganic classes. I am not a bioinorganic chemist. This was a great activity for both my students and myself. There was great discussion and the students gave very good feedback on the activity. 

Fri, 06/22/2018 - 17:31 Permalink