How would you characterize the tone of the narrator at the start and end of chapter 1?
Chapter 1 of James Joyce's A Portrait of the Artist as a Young Man begins with a very early episode from a young Stephen Dedalus's life. In this chapter, Joyce succeeds in constructing narration that parallels Stephen's age; the first part of the novel begins as a child's story would ("Once upon a time and a very good time it was...") and is narrated in a way that seems to reflect a child's thoughts, and overall has a very elementary and childish tone.
The middle of chapter one follows Stephen's consciousness through various memories of dinners at home and experiences at his school, the Clongowes Wood College, a Jesuit school. Through reading about these experiences, readers understand Stephen to be a sensitive, pensive boy whose early memories certainly played a role in developing his later personality.
By the end of the chapter, Stephen, who has been punished unjustly, has mustered up the courage to appeal his punishment to the rector, who acknowledges Father Dolan's error. As the page linked below explains, the tone of the end of Chapter 1 is triumphant; despite his fears, Stephen has found the courage to challenge an authority figure (and it's significant the authority figure is a priest, as Stephen later rebels against religion), and has won. His peers celebrate his victory, and the end of the chapter, Stephen is left with feelings of pride and accomplishment.