GENERAL KNOWLEDGE

Detailed explanation-1: -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.

Detailed explanation-2: -The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups. Groups are labeled at the top of each column.

Detailed explanation-3: -Reason: Elements in a group have the same number of electrons in the outermost shell hence they have similar chemical properties.

Detailed explanation-4: -The vertical columns (groups) of the periodic table are arranged such that all its elements have the same number of valence electrons.

Detailed explanation-5: -The physical and chemical properties of elements depend on the number of valence electrons. Elements present in the same group have the same number of valence electrons. Therefore, elements present in the same group have similar physical and chemical properties.