Clarification details
Updated April 2016.
This standard involves demonstrating an understanding of oxidation-reduction.
Achievement standard requirements
A table/list of names of substances, their formulae and appearance can be provided. However, these substances must not be linked as reduction-oxidation couples/pairs.
Making judgements
The following requirements should be met for both oxidation and reduction processes.
For all levels of achievement students need to identify the name or formula of oxidation-reduction species and describe the process as either oxidation or reduction with reasons (the loss/gain of electrons or change in oxidation number).
Merit also requires students to show in-depth understanding by writing balanced half equations and linking these to observations and oxidation–reduction with reasons (the number of electrons lost/gained or change in oxidation number).
Excellence also requires students to show comprehensive understanding of oxidation-reduction by linking balanced half equations, a correct overall equation, observations and electron transfer or change in oxidation number.