Answer:
The correct answer is fluorine (F)
Step-by-step explanation:
The property described in the question is electronegativity. Electronegativity is the tendency of an atom to attract a shared pair of electron towards itself. Elements with few electrons on there outermost shell tend to have a lower electronegativity than those that have more electrons on there outermost shell; this is because it is easier for elements to attract few electrons and achieve there octet configuration than to attract more electrons. Hence, electronegativity increases across the period. Also, the fewer the electron shells, the higher the electronegativity; this is because electrons are more tightly bound to the nucleus when they are closer to it. Hence, electronegativity decreases down the group since the number of shells increases down the group.
From the above explanations, it can be deduced that fluorine has the highest electronegativity since it has just two shells (in period 2) and needs to attract just one electron towards itself.