This event was light/calm but also mysterious because the story states "The morning of June 27th was clear and sunny, with the fresh warmth off a full summer day; the flowers were blossoming profusely and the grass was richly green." It's saying that it was a chill day and families were getting ready for the lottery. Something mysterious happened when Bobbie Martin put stones in his pockets. The text states "Bobby Martin had already stuffed his pockets full of stones."
The tone in this scene is neutral, because the narrator is writing calm and in a mild tone. The text states " Mr. Summers said soberly, "guess we better get started, get this over with, so's we can go back to work. Anybody ain't here?"
The tension between everyone became more suspenseful, the votes were in and Tesse "won the lottery". So they stoned her to death. It became quite , the text stated "It's Tessie," Mr. Summers said, and his voice was hushed. "Show us her paper, Bill."