Some metacognitive mental activities were explored on chemical reading activities as specific judgments called metacognitive judgments. A think-aloud protocol was carried out to fifteen chemistry teacher candidates to express their judgments on chemical reading activities for question posing. Two chemical articles were designed to stimulate these judgments that were deepened by twenty open-ended questions of metacognitive judgment exploratory. A phenomenological reduction method was used to analyze the reading pattern and the question responses. The findings indicated that the chemical reading characteristics, the nature of the readers, and the perception toward the task demand had contributed to both the difficulties (ease-of-learning) and the work of memories (judgment-of-learning) on chemical reading activities. Some initiation factors were identified constructing the feeling states on the reading activity including the terminating strategy patterns (feeling-of-knowing). Confirmations of the memories used during the reading activity were divulged from seeking the familiarity to decide the memories (sourcemonitoring judgment). Expressions about the judgments were also disclosed quantitatively and qualitatively (retrospective belief) as goal-oriented and processoriented reader types. Based on the finding, the metacognitive judgment in chemical reading activity could be improved by designing the metacognitive chemical articles that determine the task, the sequence of intra-disciplinary chemical topics, the title-rooted phrases or clauses, chemical representations, terminologies, and interactive statements.