Oral Presentation Royal Australian Chemical Institute National Congress 2026

Implementing IUPAC Oxidation State Recommendations (2016) in a Secondary School Science Curriculum learning environment. (134171)

John Drew 1
  1. Department for Education, South Australia, Flinders Street, SA, Australia

The fifth edition of Compendium of Chemical Terminology in 2018 for International Union of Pure and Applied Chemistry (IUPAC) included a non-analogous definition for oxidation state (1). The tertiary level definitions used were deconstructed for access by secondary school educators by directly referencing the Compendium source material (2). In particular, use of an LCAO-MO model to support the non-analogous definition and the consequent Algorithm of Assigning Bonds alongside the Algorithm of Summing Bond Orders were framed within the development of a secondary school introduction to atomic structure and chemical reactions. This procedure is detailed in ‘Redox Reduxed’ (3) including links to the resultant learning materials for secondary schools.

A significant concept described in the source material was the extent to which bonded electron pairs shift between atoms (4 pp. 209-211) from 100% non-ionic (covalent) in nature to being a theorised 100% ionic in nature, labelled as ‘ionicity’. Wikipedia (5) currently cites the 2018 IUPAC definition for oxidation state with reference to ionicity, but without explanation or elaboration about what ionicity is. Online dictionaries, e.g., (6) and school study guides, e.g., (7) provide definitions including ‘transfer of electrons’ which are in contradiction of the following earlier concerns regarding the need for a non-analogous definition.

“It is suggested that writers avoid defining oxidation (and related terms) as ‘transfer of electrons’ in favour of a definition involving change of oxidation state.” (8)

Work continues to implement the necessary concept development in support of IUPAC recommendations over a secondary school cycle using a spiral curriculum framework (9) presented in visually accessible formats (10). Learning tasks to be presented at this session include emission spectroscopy to support Periodic Table trends, including Allen electronegativities to support bond direction as ionicity and therefore bond type and structure (11) within each recommended Algorithm to determine Oxidation State.

Keyword Terms: IUPAC Oxidation State Recommendations; Electrochemistry misconceptions; Ionicity; Bond Direction; Electronegativity; Chemical Bond Types

Teacher Bio: John Drew is a public sector science and chemistry teacher at Charles Campbell College. He continues to apply his educational interests from his HDR Master of Educational Research and delivering Chemistry Curriculum Methodology courses to Grad Dip Ed, Master of Teaching, and B.Ed. students at the University of Adelaide. Those interests remain inspired by his so long-ago BSc in Physical Chemistry and Grad Dip Ed from Flinders University. He participates in sharing professional knowledge within the South Australian Science Teachers Association (SASTA) by attending and presenting sessions Conferences and as a contributor to the Australian Science Teachers Association (ASTA) Journal Teaching Science.

  1. 1. IUPAC. IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry. [Online] 2025. [Cited: 8 December 2025.] https://goldbook.iupac.org/terms/view/O04365.
  2. 2. Karen, P, McArdle, P and Takats, J. Comprehensive definition of oxidation state (IUPAC Recommendations 2016). [Online] 2016. [Cited: 8 December 2025.] https://www.degruyterbrill.com/document/doi/10.1515/pac-2015-1204/html.
  3. 3. Redox Reduxed: Application of a non-analogous definition for oxidation state (Peer reviewed paper). Drew, John. 3, 2020, Teaching Science - The Journal of The Australian Science Teachers Association, Vol. 66, pp. 5-15.
  4. 4. Barke, H, Hazari, A and Yitbarek, S. Misconceptions in Chemistry - Addressing Perceptions in Chemical Education. Berlin : Springer-Verlag, 2009. 978-3-540-70988-6.
  5. 5. Wikipedia. Oxidation State. [Online] 2025. [Cited: 8 December 2025.] https://en.wikipedia.org/wiki/Oxidation_state.
  6. 6. New Generation Dictionary. ionicity Meaning. [Online] 2024. [Cited: 8 December 2025.] https://goong.com/word/ionicity-meaning/.
  7. 7. Morgante, K, Starczak, L and Tulip, S. Topic 6: Redox Reactions. Chemistry SACE 1 Workbook - Essentials Education. Adelaide : Adelaide Tuition Centre, 2022, pp. 244-247.
  8. 8. Vitz, E. Redox Redux: Recommendations for Improving Textbook and IUPAC Definitions. [Online] 2002. [Cited: 8 December 2025.] https://pubs.acs.org/doi/10.1021/ed079p397.
  9. 9. Johnston, H. The Spiral Curriculum. Research into Practice. [Online] 2012. [Cited: 9 December 2025.] https://eric.ed.gov/?id=ED538282.
  10. 10. Tufte, E. Envisioning Information. 8th. Cheshire, Connecticut : Graphics Press, 2001.
  11. 11. Silverstein, T. Oxidation and Reduction: Too Many Definitions? [Online] 2010. [Cited: 8 December 2025.] https://pubs.acs.org/doi/10.1021/ed100777q?ref=recommended.