Where do you find elements grouped that have the most similar physical and chemical properties?
a. horizontal periods
b. left side of the table
c. in vertical groups or families
d. right side of the table

The right option is; c. in vertical groups or families

In the periodic table of elements (a table in which all recognized elements are arranged in an informative series), elements grouped that have the most similar physical and chemical properties are placed in the vertical columns of elements known as groups or families. For example all of the group 1A elements possess one valence electron and have similar chemical and physical properties. Group 2A elements are alkaline earth metals and they also have similarities in electron configurations.

looks like the answer is     c     to me!