What is a wave coming into a barrier

Dalton’s model of an atom is the best described as a) a solar system b) a solid sphere c) a cloud d) a scoop of chocolate chip ice cream

Aknife blade is a(n) a. lever b. screw c. wedge d. inclined plane

The experiment was repeated many years later but the gases were mixed in a different type of container. a white solid was obtained which was xenon fluoride. predict whether you think 1) krypton and 2) radon will react with fluorine. explain reasons for your predictions