Answer : The correct option is, It increases across a period and decreases down a group.
Explanation :
Electronegativity : It is defined as the tendency of an atom or an element in a molecule to attract the shared pair of electrons towards itself.
That means, the higher the electronegativity of atom the higher will be its ability to attract shared electrons.
Electronegativity of the elements increase across a period and decreases down a group.
As moving from left to right in a period or across a period, the electrons are added to the same shell and the nuclear charge increases that means the outer shell electrons become close to the nucleus and thus, ability of elements to attract shared pair of electrons itself increases.
As moving from top to bottom in a group or down a group, the electrons are added to the new shell that means the outer shell electrons become far to the nucleus and thus, ability of elements to attract shared pair of electrons itself decreases.
Hence, the correct option is, It increases across a period and decreases down a group.
