Question

how does the electronegativity of elements vary as we move:
i) down the group
ii) across the period??

Answer 1

1) Electronegativity of a  and element decreases from top to bottom in a periodic table
2) Electronegativity increases from left to right the periodic table

Answer 2

1) On moving down a group the metallic character increases and non metallic character decreases. i.e. electronegativity decreases
2) on moving from left to right in a particular period the metallic character decreases and non metallic character increases i.e. electronegativity increases.