Chemistry exercises are valuable tools in teaching and learning chemistry, helping develop students' representational competency per the 2018 Curriculum for General Education. To meet this objective, this article proposes a system of exercises on the topic of “Elements in group VIIA”. Theoretical research methods provide the basis for building exercises and suggest methods that could be applied to teaching and learning processes. Statistical and practical techniques are used to test the feasibility and effectiveness of the study. The post-experiment was carried out at Kim Bang A High School with the participation of 41 students. Through statistical processing, the post-experimental evaluation shows that there is an improvement in students' representational competency. Specifically, the average score of the competency to apply knowledge and skills increased from 1.72 to 2.00 with p = 0.0312 (<
0.05) and ES = 0.82. This is the basis of using the exercise system in teaching, which could be further utilized in other topics.