Question

What is the duet rule?

Answer 1

Hint : We all know that the Duet rule helps in deciding the stability of an element and its tendency to either give up electrons or gain electrons. It is also an important rule that dictates the electronic configuration of an element.

Complete Step By Step Answer:
The duet rule states that hydrogen and helium may have no more than two electrons in their valence shells. The rule comes from quantum mechanics, which says that the lowest energy level $\left( n~=\text{ }1 \right)$ of an atom can contain only two electrons. The duet rule is also known as Octet rule.
Duet rule can be stated as the requirement of elements to possess eight electrons in their valence shell to gain stability. As mentioned above, in order for an element to fulfill the duet rule it must either lose electrons or gain electrons. After doing so, these elements resemble the characteristics of a noble gas. This phenomenon where the element that has octet configuration has particular chemical characteristics which can be important in classifying and characterizing the elements that have not yet been discovered or for elements that have yet to be added into the periodic table.
This rule is also responsible for the formation of all bonds as the bond formation occurs between two elements that do not have octet configuration For example, in covalent bonds a pair of electrons are shared. In an ionic bond, an electron is transferred from one element to another. This is also important in formation of anions and cations. As an anion is formed by an element by accepting electrons and a cation is formed by an element by donating or releasing electrons.

Note :
Remember that the duet rule is used to provide stability to an atom. An element that finally attains the octet configuration will become inert and chemically unreactive. The duet rule also dictates the formation of bonds between two chemical species.