What quantity is the same among atoms of the same element?

Neutrons or Neutral atoms

Explanation:

Neutral atoms of each element contain an equal number of protons and electrons. The number of protons determines an element's atomic number and is used to distinguish one element from another.

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.