All of the elements in a family or group have similar chemical properties. Which of the following statements best explains why this is true?
A. The elements in a group have the same number of protons in their nuclei.
B. The elements in a group have similar atomic mass numbers.
C. The elements in a group have the same number of valence electrons.
D. The elements in a group have similar atomic numbers.
I don't remember... Don't have my notes either.