The condensed structural formula provides the shortest way to understand the atoms and their numbers, their connection with respect to each other, and therefore, visualize the compounds' structure without elaborately drawing it, but by writing it in a single line.
So, if the elaborate structure of butanoic acid look like A, the condensed structural formula would look like B.
As early as 1916, G.N. Lewis knew that the central nucleus remains unaltered in every atom in the chemical reaction. And it is the electrons present in the outer-nuclear region that are exchanged between the atoms when new bonds are formed.
According to his hypothesis, a filled outer-nuclear shell of the electron in an atom is especially stable. He assumed that all noble gases (He, Ne, Ar, Kr, Xe, Rn) are stable, and it is their electron configuration that guarantees them stability and chemical inertness.
In his landmark paper, 'The Atom and the Molecule,' G.N. Lewis attempted to describe linkages between the atoms to understand the nature of covalent bonds.
He used dots to represent an atom’s valence electrons and argued that the atoms share their valence electrons to form one, two, or three bonds until they attain a stable octet electron configuration. An exception is the Hydrogen atom that attains a duplet configuration.
The octet rule could satisfactorily explain how and why the atoms of the second period formed covalent bonds by sharing. However, it could not explain why certain atoms like Boron or Phosphorous did not follow the octet rule or why the Nitrogen atom in NO has an unpaired electron.
Incomplete octet
It's Carbon's nature to form new bonds, and in its quest, it breaks away from the old ones.
The atom or group of atoms that leaves a carbonyl carbon or a saturated/unsaturated carbon to make way for the new bond is called the leaving group(s).
Curly arrows represent transformations in organic chemistry, rationalizing what happens in a chemical reaction. It shows the movement of two and one electrons while writing the organic reaction mechanism.
The movement of two electrons is shown using a double-headed arrow. For single electron movement, a single head/ fishhook arrow is used.
A charge-containing atom is called an ion.
The charges are formed when an atom gains or loses electrons. When an atom gains electrons, the extra electrons are shown as a negative charge. And, if an atom loses its electrons, the loss is expressed with a positive charge on the atom.
Pre-requisite Article- What is a Hydrogen bond?
The Hydrogen covalently bonded to an electronegative atom is called the donor atom. The donor atom is always found in between the two electronegative atoms.
The acceptor atom is the other electronegative atom that electron starved Hydrogen tries to attract.
Inorganic chemistry describes oxidation in two ways. The first method is through the loss of electrons, and the second is by the increase in oxidation number.
In substitution reactions, an atom or group of atoms is displaced and replaced by another atom or group of atoms. The displaced atom is called the leaving group. The rest of the molecule remains unaffected.
