Which statement explains why a c–o bond is
more polar than a f–o bond?
(1) at stp, carbon has a greater density than
fluorine.
(2) a carbon atom has more valence electrons
than a fluorine atom.
(3) the difference in electronegativity between
carbon and oxygen is greater than that
between fluorine and oxygen.
(4) the difference in first ionization energy
between carbon and oxygen is greater than
that between fluorine and oxygen.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."