All the elements of a family in the periodic table have what feature in common?
A) They all have similar chemical properties.
B) They all have the same number of protons in the nucleus.
C) They are all located in the same horizontal row or period.
D) They all have the same number of electrons in the electron cloud.
Explanation: Elements of any family in the periodic table have the same number of valence electrons. Because of this they all have similar chemical properties.