Which of the following elements is the most electronegative? a. fluorine b. boron c. francium d. titanium

The correct option is A

Explanation:

Electronegativity is the tendency of an atom to attract shared electron towards itself. Generally, metals have low electronegativity, this is because they have few valence electron(s) in there outermost shell and it's easier for them to lose this electron(s) than to gain electrons. Hence, Francium and Titanium are both wrong because they are both metals.

Non-metals however have an almost filled outermost shell, and hence it is easier for them to attract electron(s) than to lose. Thus, in the periodic table, electronegativity increases from left to right across the period (with group zero excluded from this trend). We can deduce from the above that halogens (in group 17) have the highest electronegativity in each period.

From the options provided, Fluorine is the answer based on earlier discussions. It should however be noted that Fluorine is the most electronegative element because it's electrons are closely bound to it's atom because the outermost shell, where the valence electrons are, is close to the centre nucleus. The force and the short distance between the positively charged nucleus and the negatively charged valence electrons makes fluorine the most electronegative element. Because it's very difficult to lose any of this electron and easier to gain an electron this way. Oxygen and Nitrogen are the next most electronegative elements because of this reasons.