Energy and matter are fundamental, yet challenging concepts in middle school chemistry due to their abstract, unobservable nature. Although it is important for science teachers to elicit a range of students' ideas to design and revise their instruction, capturing such varied ideas using traditional assessments consisting of multiple-choice items can be difficult. In particular, the linguistic complexity of these items may hinder English learners (ELs) who speak English as a second language from understanding and representing their ideas. This study explores how multi-modal assessments using different types of open-ended items can document ELs' and English-dominant students' (EDSs) understanding of energy and matter in chemistry. 38 eighth-grade, linguistically diverse students taught by one teacher at a low-income middle school completed an assessment designed to elicit their ideas about properties of matter and chemical reactions through arguing from evidence, writing explanations, and developing models of chemical phenomena. The results show that the three types of assessment items captured different correct and alternative ideas that ELs and EDSs held. In particular, modeling appears promising as a tool to assess what ELs know about properties of matter and chemical reactions in middle school chemistry, compared to other written items. The findings of this study provide insights into how different types of assessment items can be used to better understand the range of ideas held by linguistically diverse students.