Question

The highest electronegative element is:
(A) Carbon
(B) Oxygen
(C) Fluorine
(D) Nitrogen

Answer 1

Hint: Electronegativity is the tendency of an atom to attract a shared pair of electrons towards itself.
- The most electronegative atoms are present in group 17 of the periodic table.

Complete step by step answer:
So in the question it is asked that among the given options, which element has the highest electronegativity value.
- From the lower classes we are studying about the electronegativity of various elements and how they show a gradual change while moving down the group and from left to right.
- First let’s have a brief idea about what electronegativity is, how it shows trends along the period and groups and then move on to the solution part. As the solution part is the application of the periodic trends of electronegativity parameters.
- Electronegativity is the tendency of an atom to pull the shared pair of electrons or the electron density towards itself. The electronegativity of an atom is influenced by its atomic number and the distance between the positively charged nucleus and the valence electrons.
- Higher the electronegativity value, more the atom or the substituent group attracts the electrons towards itself. The opposite of electronegativity is electropositivity, a measure of an element's ability to donate electrons.
- Now let’s discuss the electronegativity trends observed in the periodic table. As we move along the period from left to right the electronegativity increase since while we move from left to right electrons are added and the effective nuclear charge is also increases which decreases the charge of the atom and hence the valence electrons are held strongly and this increases the electronegative nature of the element.
- If we go down a group even though the effective nuclear charge is increasing since the atomic number is increasing, the increase in effective nuclear charge experienced on the electrons are nullified by the addition of the new shell while moving down the group. As we move down the group new shells are added, hence atomic size increases and the electronegativity of the element decreases.
- Here if we compare the four options given i.e. C is having atomic number 6, N has atomic number7, O is having atomic number 8 and for F its 9. Hence we can conclude that all the given options are elements which belong to the same period, i.e. the second period.
- And hence now we have to apply the condition of electronegativity variation along a period.
As we move along the period from left to right, electronegative character increases, hence F is the most electronegative atom from the given options.

- Fluorine is the most electronegative element. It has an electronegativity value of 4 on the Pauling scale.
The F possesses greater electronegativity value due to its small atomic radii, the F has 7 valence electrons in their valence shell and just need one more electron to complete its octet configuration. In F the seven electrons are strongly held by the nucleus as F is smaller in size and this strong attraction of the valence electrons by the nucleus accounts for the greater electronegativity value of F.
So the correct answer is “C”:

Note: Remember that the Pauling scale is a relative scale. The electronegative values on the Pauling scale have no units. The reference is set as hydrogen as it forms covalent bonds with a variety of elements.