Within the scope of the 2018 National Textbook Plan (PNLD), books concerning the field of Natural Sciences were divided into disciplines: Chemistry, Physics, and Biology. Following the reform of the New High School (NEM), the 2021 PNLD predicts the amalgamation of these disciplines into a single textbook. Thus, an articulated examination of the arrangement of scientific concepts present in the Chemistry books of the 2018 PNLD (pre-reform) was compared with the books in the Natural Sciences area approved by the PNLD in 2021 (post-reform). The aim was to highlight the changes resulting from the NEM in Natural Sciences textbooks and the possible implications of these alterations on Chemistry Education, resulting from this new curriculum organization. As a methodological option, a qualitative documentary approach was used, constituting an exploratory study. For this purpose, two collections of books approved by the PNLD in 2018 and 2021 were selected for analysis. Content analysis was used as the analytical method. Four categories were used as parameters, two a priori, simple conceptual approach and broad conceptual approach; and two a posteriori, partially simple conceptual approach and partially broad conceptual approach. The predominance of the broad conceptual category in the 2018 PNLD, contrasted with the notable reduction in this category in the 2021 editions, suggests the need for further investigations into other thematic units and collections of Natural Sciences. Such studies could gather additional evidence regarding the lack of fundamental scientific concepts, which may impact students’ civic education in the context of the New High School.
