Question

4 Explain why elements in Groups I and 6 of the periode
table have the same valency.​

Answer 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.

Answer 2

Explanation:

(1) The valency of an element is determined by the number of valence electron in the outermost shell of an atom of an element. (2) All the elements in a group have the same number of valence electrons. Therefore, elements in the same group should have the same valency.