Which of the following statements is true concerning the two nuclides and ? A) They have the same number of neutrons. B) They are isotopes. C) They have the same relative atomic mass. D) They have the same mass number. E) They have different chemical properties.

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth