Which element was arbitrarily assigned a value of 4.0 in the 'Halogens' section in 1922 by Linus Pauling, an American scientist?

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This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 18 Jul 2023 Shift 4)

Answer 1

The correct answer is Fluorine.Key Points

Fluorine is the element that was arbitrarily assigned a value of 4.0 by Linus Pauling in the 'Halogens' section in 1922.
Linus Pauling was an American chemist who developed the concept of electronegativity, and he assigned fluorine the highest electronegativity among all elements.

Additional InformationMajor points on electronegativity and Linus Pauling's contribution:

Electronegativity: Electronegativity is a measure of the ability of an atom to attract the shared pair of electrons towards itself in a covalent bond.
Linus Pauling: Linus Pauling, an American chemist and two-time Nobel laureate, is widely known for his work in quantum chemistry and molecular biology. He introduced the concept of electronegativity in 1932.
Pauling Scale: Linus Pauling proposed the most commonly used electronegativity scale, known as the Pauling scale. This scale is dimensionless and ranges from 0.7 for francium (the least electronegative element) to 4.0 for fluorine (the most electronegative).
Fluorine: In Pauling's scale, he arbitrarily assigned a value of 4.0 to fluorine, the highest among all elements, as it has the highest ability to attract electrons towards itself in a chemical bond.
Significance: Electronegativity is a critical property used to predict the nature of bonds in a molecule (whether it will be ionic, polar covalent, or nonpolar covalent) as well as the polarity of the molecule itself.

Important Points

Element	Atomic number	Electron configuration	State at room temperature	Key Uses/Applications	Other Important Points
Bromine (Br)	35	[Ar] 4s2 3d10 4p5	Liquid	Used in fumigants, flameproofing agents, water purification compounds.	Bromine is the only non-metallic element that is liquid at room temperature.
Iodine (I)	53	[Kr] 5s2 4d10 5p5	Solid	Used in medicine, photography, dyes. Essential nutrient for humans.	In its elemental form, iodine occurs as a purple-black, shiny crystalline solid.
Astatine (At)	85	[Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁵	Solid	No significant uses due to its high radioactivity and scarcity in nature.	Astatine is the rarest naturally occurring element on the Earth's crust.