The size of atoms can be measured using the diffraction of x-rays. Measurements of atomic size confirm that trends can be identified
based on location on the Periodic Table of the Elements. Which
group of elements is listed in order of decreasing size?

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)