Elements on the periodic table are arranged into vertical columns called groups. Which of the following is true of the elements in a group? O All the elements in a group have the same mass.
Elements in a group have the same number of neutrons.
Elements in a group have similar properties
O Elements in a group have the same number of protons.

Elements in a group have the same number of protons.

Explanation:

The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.