Developing representational competence early in chemistry education is important. However, research to uncover students' difficulties with representational competence of basic chemical concepts in the early years of their chemistry course is scarce. The purpose of this study was to investigate and identify these difficulties. A total of 384 Malaysian Form 4 science students (mean age = 16 years) participated in this study. Five categories of representational competence were assessed. Quantitative data were obtained from an instrument namely the Test of Representational Competence (TRC). Findings showed majority of the participants encountered difficulties interpreting chemical representations (66%), making connections between representations and concepts (51%), using representations to generate explanations (73%), as well as translating between representations across the three levels: macroscopic, submicroscopic and symbolic (79%). Comparing the percent mean difficulty, it could be concluded that the participants encountered most difficulty translating between different representations across levels. Several implications arising from the findings are also put forward.