The element with highest electronegativity is?

KPSC Staff Nurse - 2018

Biochemistry and Nutrition

Easy

Appeared in: KPSC Staff Nurse - 2018

Explanation

Electronegativity is a chemical property that describes the tendency of an atom to attract electrons towards itself in a chemical bond.
In the periodic table, electronegativity generally increases from left to right across a period and decreases from top to bottom down a group.
The options provided (Chlorine, Bromine, Iodine, Fluorine) are all halogens belonging to Group 17.
Fluorine is located at the top of this group, making it the element with the smallest atomic radius and the strongest attraction for bonding electrons among the halogens.
Consequently, Fluorine has the highest electronegativity not only in its group but among all elements.

Option A: Chlorine is a highly electronegative element, but it is located below Fluorine in Group 17. Electronegativity decreases down a group.
Option B: Bromine is less electronegative than both Fluorine and Chlorine because it is further down Group 17. Its larger atomic size means the nucleus has a weaker pull on bonding electrons.
Option C: Iodine has the lowest electronegativity among the options. It is the largest atom of the four and is positioned at the bottom of this list within Group 17.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Periodic Trends: Electronegativity as background academic context rather than a clinical decision trigger.
The concept of electronegativity is fundamental to understanding the polarity of molecules and intermolecular forces, such as hydrogen bonds. These forces are critical for drug-receptor interactions, determining how effectively a drug binds to its target.
Many modern pharmaceuticals are 'fluorinated'—they contain fluorine atoms. The high electronegativity of fluorine can increase a drug's metabolic stability (making it last longer in the body) and its binding affinity to target proteins, enhancing its therapeutic effect. Examples include the antidepressant fluoxetine and the chemotherapy agent 5-fluorouracil.
What if? If the question asked for the element with the highest electron affinity, the answer would be Chlorine, not Fluorine. While related, electronegativity (attraction in a bond) and electron affinity (energy change when an electron is added to a neutral atom) are different properties with slightly different trends.

How to Approach the Question

First, identify the key concept in the question, which is 'highest electronegativity'.
Recall the general trends for electronegativity in the periodic table: it increases as you move from left to right across a period and decreases as you move down a group.
Locate the elements from the options (Chlorine, Bromine, Iodine, Fluorine) in the periodic table. You should recognize them as halogens, all belonging to the same vertical column (Group 17).
Since the elements are in the same group, apply the group trend: electronegativity decreases down the group.
The order of these elements from top to bottom is Fluorine, Chlorine, Bromine, Iodine. Therefore, the element at the top, Fluorine, will have the highest electronegativity.

Concept Tested & Keywords

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