How did knowing the number of valance elections in one of the Allen elements help identify it. Explain how the table was used to accomplish this task.

What happens to light waves from a star as the star moves away from earth?

Aplane travels 1000 miles in 5 hours .what is the planes average speed?

Apebble is thrown into a calm lake, ripples are formed from the center and move outward. the water particles in the lake travel in a circular pattern that moves up and down on the surface of a lake, and the energy travels a) diagonally. b) downward. c) horizontally. d) upward.