Answer:
Two elements in same group having similar properties.
Explanation:
The elements shows similar properties if they have same number of valance electrons.
As we move left to right in periodic table the number of valance electrons increases in case of every element
When we move top to down in the group of periodic table the number of valance electrons remain same. So the elements in same group shows similar properties.
For example:
Fluorine and chlorine are present in same group, both have same valance electrons so they shows similar properties.
Electronic configuration of fluorine.
F₉ = [He] 2s² 2p⁵
Electronic configuration of chlorine.
Cl₁₇ = [Ne] 3s² 3p⁵
Both have same number of valance electrons that's why showing similar physical and chemical properties.
