Question #17f5a

1 Answer
Apr 1, 2017


I believe the answer is C.


The atomic number and number of electrons increase as the atomic mass increases, with few exceptions. If you think about it, the periodic table is arranged according to the atomic number (the number of protons), which corresponds to the atomic mass (with few exceptions). There is no repetition here.

The size of the atoms increases down a group and decreases across a period. There is a pattern, but, since the size increases overall, it's not really a repetition.

The chemical properties do repeat, though. Elements in the same group have similar properties since they have the same number of valence electrons.