The chemistry curriculum in Germany follows the same structure as applied by the three sub-units: students first learn to observe and explain phenomena on a macroscopic level and to carry out simple experiments, mostly based on given instructions. Often in their second year of chemistry, particle models and the big idea of atoms are introduced and applied for different explanations. Further on, such models are specified and differentiated.
The National Standards for all German states structure the chemical content by four so-called basic concepts: (1) matter and particles, (2) structure-property-relations, (3) chemical reaction and (4) energy changes based on chemical processes. The three sub-units of this unit focus mainly on the concept of structure-property-relations.
The first sub-unit can be integrated in the curriculum of the first year in science or chemistry, often year 5 or 6 (age 10 - 12). In almost all German states, curricula demand the observation, description and identification of substances at this level, also their separation and first experimental analyses.
Sub-unit 2 can easily be connected to the curriculum topic of acids and bases which is usually treated on a submicroscopic level around year 9 (age 13/14). The students classify acids and bases using the definitions by Arrhenius or Brönstedt.
Sub-unit 3 builds on knowledge on organic substances and introduces or rather enlarges the knowledge about polymers. This will be dealt with in upper secondary level courses.