Question

Which of the following has the highest electronegativity?
A. $C$
B. $Mg$
C. $$O$$
D. $S$

Answer 1

Hint: Electronegativity is the tendency of an element to attract a shared pair of electrons. According to the trend, on moving from left to right in a period in the periodic table electronegativity increases and on moving from up to down in a group electronegativity decreases.

Complete answer:
Electronegativity is the tendency of an element to attract a shared pair of electrons that is the electron density. Electronegativity is represented by the symbol $\chi$ . Electronegativity of an atom depends on the atomic number and its atomic radii. There is a trend of electronegativity in the periodic table. According to the trend, on moving in a period from left to right the electronegativity increases and on moving in a group from up to down the electronegativity decreases.
On following this trend the order of electronegativity we will get:
$Mg<S<C<O$
So, oxygen has the highest electronegativity among all.

Hence, option C is correct.
Additional information:
There is also a property of element that is electropositivity. Electropositivity is defined as the ability of an element to donate electrons. And after donating electrons they form positive ions. Generally, electropositivity is directly proportional to the metallic character. So, the alkali metals are the most electropositive among all the metals. This is due to the presence of a single electron in their valence shell and, as this is relatively far from the nucleus of the atom, it is easily lost; in other words, these metals have low ionization energies.

Note:
Electronegativity of elements increases as we move along the periods in the periodic table, and decreases down as we move along the groups but on the other hand electropositivity decreases as we move along periods and increases as we go down the groups. So, we can say that elements in the upper right of the periodic table of elements will have the greatest electronegativity, and those in the lower-left will have the greatest electropositivity.