At the end of the article, you will able to describe why the electronegativity chart has a variation in values. Let’s get started. The tendency of an atom in a compound or molecule to attract the shared electrons towards itself is called as electronegativity of the atom.
- Electronegativity and electron-affinity both are measured as the electron-attracting power.
- Being relative in Nature, E.N has no specific units.
- Its value is not constant. It simply depends upon the nature of the atom with which a particular atom is linked.
Difference between electron affinity and electronegativity
|It is the capacity of an atom in a molecule or compound to attract the bonded electrons.||It is the capacity of an isolated atom in a free state to attract an electron|
|It is the relative value of an atom.||It is the absolute value of an atom.|
|It varies regularly in a period or a group.||It does not change regularly in a period or a group.|
In Electronegativity Chart, Electropositive elements have low electronegativity values and Electronegative elements have high E.N values. The highest electronegative element in the periodic table is ‘F’. The lowest electronegative element in the periodic table is ‘Cs’ and ‘Fr’.
The group of elements which shows same electronegative character is following.
|1)||N and Cl||3.0|
|2)||H and P||2.1|
|3)||C, S and I||2.5|
|4)||Cs and Fr||0.7|
- In a period: As we move from left to right along a period the electronegativity increases, this is due to decreases in size with an increase in nuclear charge.
- In a group: As we move from top to bottom within a group, the value of electronegativity decreases due to increase in size. Reason – Less nuclear attraction and Higher atomic radius.
- The inert gases have zero electronegativity, due to fully filled outermost shell electronic configuration.
- The alkali metals have the lowest value of electronegativity where the halogens have the higher value of electronegativity.
The misconception is that the value of electronegativity of 5d-series is lesser than that of the value of the 4d-series. But the concept is that the value of electronegativity of 5d series is greater than that of the value of 4d series. It is due to lanthanide contraction because the nuclear charges of 5d series elements increase with 32 unit against 4d.
This is all about the basics that why electronegativity chart has a variation in values.
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