Band 5, Heft 4

Relativistic effects are important to understand the chemistry of heavier elements across the periodic table (PT). Three important relativistic effects are: contraction of s - and p -orbitals (direct relativistic effect), expansion of d - and f -orbitals (indirect relativistic effect) and spin–orbit (SO) coupling to split the p -, d - and f -orbitals. Each of these effects is approximately proportional to Z 2 ( Z  = atomic number) for the valence shell electrons in many electron atoms and consequently, these relativistic effects dominantly control the properties of the heavier elements (mainly the 6th and 7th period elements). These aspects are not given the proper importance in most of the inorganic chemistry text books and in chemistry education at the university level.

In a teaching context based on the competency approach, the creation of an appropriate teaching-learning environment requires, among other things, teachers to master the meaning of the concepts taught and teaching-learning activities designed according to the constructivist approach and the investigative approach. In this article, we focused on the operating principle of the Daniell cell. The research study involved identifying the epistemological gaps of 58 future teachers in relation to the concepts describing the previous theme via an open questionnaire, as well as the degree of compliance of the activities proposed in the textbook with the curricular guidelines. The main results showed that the respondents had not mastered the meaning of the positive and negative poles of a cell or the concept of its electrical voltage. With regard to the textbook studied, we found that the design of the activities did not comply with the principles of the competency-based approach and the spiral progression of knowledge. To overcome these constraints, we propose pedagogical designs aimed at reinforcing and developing the skills of teachers and learners while progressing in the spiral of knowledge.

Engaging students in collaborative learning fosters the expression of ideas, deepens understanding, and hones argumentation skills. Argumentation is pivotal, and instructors should facilitate opportunities for its practice. In the study on an environmental chemistry course, class conversations were recorded to analyze students’ contributions to online learning. Participants shared opinions, raised objections, and built on others’ answers. The instructor played a crucial role in harmonizing collaboration and guiding comprehensive argumentation. The study found claims and data as the most basic and common elements of argumentation. However, more complex components like rebuttal and backing warrants often need instructor intervention. While claims and data typically relied on one form of representation, such as macroscopic or symbolic, warrants demanded multiple dimensions, predominantly symbolic and submicroscopic. Toulmin’s arguments and Mahaffy’s tetrahedral ability of chemical representation were used for analysis. The findings highlighted that argumentation skills and chemical representation are intertwined, with certain argumentative components calling for specific representational dimensions. Collaborative online learning, thus, can enhance student participation and multifaceted skill development.

Existing instructional materials for chemistry offer a huge range of different external representations that can be used by chemistry teachers to support students’ understanding of chemical concepts like the concept structure of matter . In science, different kinds of representations are usually combined forming multiple external representations. Examples are combinations of texts, pictures, figures, diagrams, graphs, tables, schemes etc. However, these multiple external representations often have problematic features and/or do not meet students’ subject-related learning needs. For example, many external representations do not take different representational levels into account and/or mix information on the macroscopic level with those from the submicroscopic level. Such representations have the potential to favor students’ misconceptions who often struggle with separating different representational levels. Therefore, it is important to highlight crucial characteristics of external representations that potentially facilitate students’ learning of chemical concepts at lower secondary schools (age group 10–14). When chemistry teachers consider and reflect crucial characteristics of representations and adapt existing external representations or develop new ones, these new representations can become powerful cognitive tools helping to make instruction in chemistry more effective and coherent. This article answers the question What makes representations good representations in science education? by describing features of effective learning with decisive characteristics of multiple external representations and highlighting these characteristics by means of concrete examples from chemistry learning. Finally, an online tool will be outlined that can help teachers to improve multiple external representations for use in chemistry classes.

This educatory experiment uses an inexpensive pH meter to determine an approximate negative logarithm of the acid dissociation constant (p K a ) value of 4,4′-trimethylenedipiperidine (TMDP). Using a pH meter and statistical data analysis by Excel tool presents an excellent opportunity to deepen student engagement with the Henderson-Hasselbalch equation and acid/base dissociation constant ( K a / K b ). Furthermore, students understand the importance determination of K a / K b and its relationship with the concentration and strength of acid/base. Four different concentrations of TMDP aqueous solutions were prepared and a series of pH readings were collected using a calibrated pH meter. Some statistical parameters were calculated and analyzed using the statistical program in Excel. Finally, students identified an unknown p K a for TMDP and compared their obtained value with a predicted p K a using software like ChemAxon. The experiment is inexpensive, safe, simple, and clean, and less experienced students can perform it. In addition, all pH recordings can be readily accessible for analysis and descriptive statistics by the Excel formula.

A Hypo helmet is a fabric hood soaked with an aqueous solution of two sodium salts for the detoxication of chlorine that was developed during the First World War. Herein, we report on a lecture, developed for non-chemistry majors that used the Hypo helmet to highlight the physical and chemical properties of chlorine. The lecture consisted of the following three components: (1) a brief introduction to the First World War (the Chemists’ War), (2) video demonstrations of the generation of chlorine by mixing bleaching powder and hydrochloric acid and the detoxication of chlorine using a dummy Hypo helmet, and (3) students’ written impressions of the lecture. The students’ written impressions revealed two things: the lecture on chlorine and the Hypo helmet was well received, and most of the students (71 %, N  = 82) did not know that chlorine was used as a poisonous gas during the First World War.

Problem-solving is an important component of chemistry teaching and learning. It often requires both conceptual knowledge and problem-solving skills. This study aims to examine how students solve tasks related to proton 1 H NMR spectroscopy. This study included 24 voluntary participants enrolled in second-semester organic chemistry labs in two different instructional settings (online or in person). The data were collected through interviews conducted via Webex video conferencing software and used a think-aloud protocol. The data were analyzed using an inductive coding approach to identify students’ problem-solving approaches and resources they used when solving a given 1 H NMR task that involved matching protons in a compound to specific peaks in the spectrum. The resources framework was used to capture students’ conceptual resources and problem-solving approaches. Results revealed that participants used more productive approaches than unproductive approaches while solving the problem; however, most students relied on one basic NMR concept to draw conclusions about the identity of a given peak. Also, when we observed the problem-solving resources that students utilized based on how they received NMR instruction (online or in-person), we did not observe major differences between the problem-solving resources that students used.

Chemical Quest is an innovative trivia game based on the 102 elements of the periodic table from H to No, developed collaboratively by upper secondary school and university teachers with the aim of increasing the interest of young students (age 14–18) in chemistry. As part of the project, a software version of the game was successfully played in 24 classes. ‘Challenging, sometimes difficult, highly instructive, relaxing, captivating, ….’ are some of the positive comments by students and teachers. In addition, Chemical Quest was conceived to be adaptable since the rules can be modified and the cards can be selected to match the educational objective.

During the COVID-19 pandemic, the unexpected lockdown of schools brought many challenges to redesigning the teaching and learning of chemistry at the secondary schooling level. The demand for online teaching under COVID-19 conditions was, however, also an opportunity to reflect on introducing new content, pedagogies, and media. This paper reflects on the implementation of a chemistry lesson plan focusing on the socio-scientific issue of ethanol used for hand sanitizers in Italy. Ethanol is possibly the most common ingredient of hand sanitizer lotions and provides an authentic context for the learning of and about chemistry. The objective was to promote students’ awareness of the deep interconnections between science, society, ethics, and the environment through a socio-scientific issues-based approach.