The most electronegative element is fluorine, which is located in the halogen group (Group 17) of the periodic table. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Fluorine has the highest electronegativity value because of its small size and the high effective nuclear charge it can exert on the bonding electrons. The outermost electronic configuration of an element determines its chemical properties including its electronegativity.

The general outer electronic configuration of Group 17 elements (halogens) is $$ns^2 np^5$$. This configuration indicates that in the outermost shell, there are two electrons in the s orbital ($$ns^2$$) and five electrons in the p orbitals ($$np^5$$). These elements require only one more electron to achieve the stable electronic configuration of a noble gas (which has a full valence shell). This high affinity for electrons is what makes the halogens, and fluorine in particular, very electronegative.

Therefore, the correct answer is:

Option C: $$ns^2 np^5$$