8 junio, 2024

8 Contributions by Gilbert Lewis and Linus Pauling

The contributions from Gilbert Lewis and Linus Pauling revolutionized the modern scientific field, their research in physicochemical areas was, and is, of vital importance in different branches of chemistry and biology.

Linus Pauling (1901-1994) was an American physical chemist, whose name became known for his research on chemical bonding and molecular structures.

He was a student at the University of Oregon, a region in which he developed the vast majority of his theories and foundations. His research began to bear fruit around 1930, while he was a professor of chemistry at the University of Oregon.

From 1927 to 1964 he managed to create the current bases of molecular study, reducing chemistry to physics. Your book The nature of the chemical bond It is the book with the most references cited by the scientific community and one of the most important publications in contemporary scientific history.

Gilbert Newton Lewis (1875-1946) carried out important studies on the peripheral electrons of atoms, among other very important contributions that will be named below.

His work as a professor of physical chemistry and dean at the University of California was definitely fruitful.

Linus Pauling and Gilbert Lewis, both scientists and professors, were instrumental in the development and understanding of new research methods.

The first boosted current research on the nature of chemical bonds, and the second evidenced the nature of nucleons and the officialization of thermodynamic chemistry.

Contributions by Gilbert Lewis

cubic atom

The Lewis atomic model is considered a previous version of the current atomic model, whose valence electrons are located within a hypothetical cube used as a reference to represent the atomic structure.

This model was useful to also formalize the concept of valence, which would be nothing more and nothing less than the ability of an atom to combine to form a compound.

the octet rule

It was in 1916 when Gilbert Newton Lewis announced that the atoms of the periodic system tend to obtain their last energy levels with 8 electrons, so that their configuration is stabilized, even equaling that of a noble gas.

This rule is applicable in the bonding of atoms that will determine the nature, the behavior and the attributes of the molecules.

heavy water

In 1933, by electrolysis, the first sample of heavy water in its pure state, deuterium oxide, an isotope of hydrogen instead of a hydrogen-1 or protium isotope, was separated, making it 11% denser than water. light.

Lewis structure

It is the molecular structure in which the valence electrons are symbolized as points between the bonding atoms.

That is, two points mean a covalent bond, a double bond would then be two pairs of points, among others.

Electrons are also symbolized as dots, but they are placed adjacent to atoms. These are the following formal charges (+, -, 2+, etc.) that are added to the atoms to differentiate between the positive nuclear charge and the totality of the electrons.

Contributions by Linus Pauling

electronegativity

Electronegativity studies the tendency of an atom to attract an electron cloud while an atomic bond occurs.

It is used to order the elements according to their electronegativity, and was developed in 1932, leading this method to future discoveries and advances in current chemistry.

Measurements are pragmatic traits ranging from 4.0 the highest (fluorine) and a range of 0.7 to francium, all other ranges oscillating between these two denominations.

The nature of the chemical bond and the structure of crystal molecules

It is the most cited book by scientists since its publication in 1939, catapulting Pauling into the forefront of the scientific community of yesterday and today.

It was Pauling who proposed the theory of hybridization as a mechanism that justifies the distribution of valence electrons, be they tetrahedral, planar, linear, or triangular.

A hybrid orbital is combined atomic orbitals. The hybrid orbitals have the same shape and the right spatial orientation.

The number of hybrid orbitals formed is equivalent to the number of atomic orbitals that are combined, they also have a bonding zone or lobe.

Discovery of the alpha helix and beta sheet

For the alpha-helix explanation, Pauling argues that the structure consisted of a three-stranded helix, with the sugar-phosphate chain at the center.

However, the data was empirical and there were still a number of flaws to correct. It was then that Watson and Crick showed the world the current double helix that defines the structure of DNA.

Rosalind Franklin had obtained a visual sample of the helical base of DNA and it was named structure B. Her crystallographic work was essential to this finding.

The beta sheet or folded sheet was another of the models proposed by Pauling in which he explains the possible structures that a protein is capable of adopting.

It is formed by the parallel positioning of two amino acid chains in the same protein. This model was shown in 1951 by Pauling together with Robert Corey.

Serology

The field of serology was also dominated by Pauling, who then turned his mind to the interaction and dynamism between antigens and antibodies.

He even came to the theory that the reason why antigens and antibodies could be combined specifically was because of their affinity in the shape of their molecules.

This theory was called the molecular complementarity theory, and it created a wide array of subsequent experiments that, in reinforcement of this theory, would lead him down new paths in the serological field.

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *