Development of TextBook to Support Merdeka Curriculum on the Atomic Structure of Phase E

As a result of the COVID-19 pandemic, it caused very significant change in education. The learning was done online. So that makes Indonesian student lose. free curriculum also demands study, as summarized PROPELA. That's why research needs to be develop textbooks support study matter, atomic structure phase E, and test validity practicality this teaching material. This type is called Educational Design Research (EDR) with Plomp model, which is: (1) preliminary research; (2) development or prototyping; (3) assessment (not done). data from validation insulated using Aiken's v formula, while registered analyzed present-day way. Based on study's results, material has been valid, an average score 0.91. use scripture easy understand view, practical learning, benefits teaching, 72%. coursebook valid helpful through formative tests have carried out. final value 0.94 proof validity. In addition, equipped mental model problems are proven help students solve existing problems. known responses active excellent solving these time spent working questions sufficient, so only uses outside hours.