The argon molecules become solid when the temperature decrease from 20C to -190 C.
The changes in arrangement and movement of the particles of the argon occurs as the temperature of the air decreased because the argon gas begins to freeze. The freezing point of argon is -189 Celsius so when the temperature decrease from 20C to -190 C, the argon molecules becomes solid.
So we can conclude that the argon molecules become solid when the temperature decrease from 20C to -190 C.
Learn more about argon here: https://brainly.com/question/23949935
#SPJ1