<u>The have </u><u>same number of valence electrons</u>
<h2>Explanation:</h2>
The elements in the same group has similar number of valence electrons. For instance All the alkali metals in Group 1 have 1 valence electron, so they all tend to react the same way with other substances. The elements in each group have the same number of electrons in the outer orbital which are responsible for the chemical properties of element so we can say that each family has the same chemical properties.
