Question

How does the elements having similar properties are placed in the same group or period?

Answer 1

Answer:

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.

Answer 2

Answer: In a periodic table the chemical elements are arranged in increasing atomic number order.

Each atom is made up of protons, neutrons and electrons and according to the atomic size periodic table is arranged.

The chemical elements in the vertical columns are knows as groups. The chemical elements in the horizontal rows are known as periods.

In a group or period all the elements have similar chemical properties. Since they have the same number of outer electrons and also the same valency they are put under one group or period.