This research aims to develop atomic structure e-module based on ePUB and find out their validity and applicability to support basic chemistry courses based on blended learning. This development research uses the Borg and Gall models. The research consists of five steps, analyzing the product to be developed, developing initial products, validating experts and revisions, field trials, and analyzing the result of trials and product revisions. The research subject consisted of three experts and

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... students of science education study program at Hasyim Asy'ari University. Research data collection techniques using Likert scale questionare 1 – 4. The result of the research were analyzed quantitatively showing the e-module that have been developed to meet the validity and appropriateness to support basic chemistry courses based on blended learning.