Question

the periodic table is organized into vertical groups of
a. elements with similar properties.
b. compounds with different properties.
c. elements with all the same chemical properties.
d. compounds with all different physical properties.

Explanation:

The periodic table arranges elements. Elements in the same vertical group have similar chemical properties due to the same number of valence - electrons. Compounds are not the basis of vertical - group organization in the periodic table. Also, elements in a group don't have all the same chemical properties exactly, just similar ones.

Answer:

A. elements with similar properties