Explanation:
As ions of the elements oxygen (O), sulfur (S), and selenium (Se) usually have charges of 2-. This means that all these elements are same group elements, that is, group 16.
And, it is known that elements of the same group tend to show similar chemical properties because they contain same number of valence electrons.
Similarly, ions of the elements fluorine (F), chlorine (Cl), and bromine (Br) usually have charges of 1-. Hence, all these elements are also of same group, that is, group 17.
Thus, we can conclude that the given situation demonstrates that elements in the same group share certain properties, and each group has unique properties.
