What is the electronegativity trend of elements in the same chemical group that form an anion?

Hint: In order to solve this question as it is related to the electronegativity so we will first learn the term electronegativity then we will see the trends how the electronegativity varies on group from top to bottom.

Complete step by step answer:
For solving this question we will define electronegativity:
We know that the higher the electronegativity of an atom, the greater its attraction for bonding electrons. Electronegativity is related to ionization energy. Electrons with low ionization energies have low electronegativities because their nuclei do not exert a strong attractive force on electrons. Elements with high ionization energies have high electronegativities due to the strong pull exerted on electrons by the nucleus. In a group, the electronegativity decreases as atomic number increases, as a result of increased distance between the valence electron and nucleus.
For example : the halogen group as we move down the group from fluorine to astatine the electronegativity value decreases.

Note: While solving this type of question we should keep in mind an exception is present in groups 13-16, going from row 2 to 3, where atoms of elements in row 3 have greater electronegativity than atoms of elements in row 2. This is because the row 3 element follows the d-block, where 10 extra electrons have been added in the next n down, so don't fully shield the valence electrons from the nuclear charge.