Answer:
1. atomic weight
the average relative mass of each element
2. isotope
one or two or more atoms of the same element with different masses due to different numbers of neutrons
3. period
a horizontal row on the periodic table
4. periodic
something that repeats itself on a regular, predictable basis
Answer:
How fast he can get through the pipe and to the flag. JK.
He is investigating the average speed of the bowling ball
Maybe you could drop a ball?