be in the same group. be in the same period. have nearly the same mass. have the same number of protons.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Copper and gold have similar reactive properties. On the Periodic Table of the Elements, these elements are most likely to
Possibilities:
- be in the same group.
- be in the same period.
- have nearly the same mass.
- have the same number of protons.

be in the same group.