Developing students' algorithmic and computational thinking is currently a major objective for primary and secondary education in many countries around the globe. Literature suggests that students face at various difficulties in programming processes, because of their mental models about basic programming constructs. Arrays constitute the first data structure students have to cope with in introductory programming courses. This paper presents the results of an empirical study on secondary education students' misconceptions and mental representations of the array data structure. Students' responses to written tasks regarding short code segments were mapped to the different levels of the SOLO taxonomy, in order to identify how students use arrays to solve programming problems. The analysis of the results showed that the majority of the students tended to manifest responses assigned to the lower SOLO levels, i.e. prestructural, unistructural and multistructural. The findings indicate that many students in the sample had incomplete or faulty representations of the array concept, which seem to be connected to their misconceptions about the programming variable concept.