3. The electron dot structure for an unknown element (Z) is shown below. :Z:
Examine the electron dot structure for the unknown element Z. Which element would have an
electron dot structure that is different from that of element Z?
A. Argon
B. Helium
C. Radon
D. None of the above

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