Question

How many electrons are in a shell?

Answer 1

The planetary model of an atom was created by Neil Bohr. He was the first to suggest that the properties of the elements have a regular pattern. The electronic structure of an atom is based on the “Bohr atomic model.” He was the first to describe the arrangement of electrons in different orbits/shells (electronic configuration).

Complete answer:
Electrons orbit the nucleus in an atom, while protons and neutrons reside within the nucleus. Bohr proposed that electrons are distributed in electronic shells that are circular in shape (orbits). These electrons travel a fixed distance around the nucleus in orbits.
The electronic configuration of an element refers to how electrons are arranged in different shells and subshells.
Rule 1: The formula $2{n^2}$ calculates the maximum number of electrons present in a given shell, where “n” is the shell number. The first shell, for example, is the K shell, which can hold up to $2({1^2})$ =$2$ electrons. The second shell is the L shell, which can hold up to $2({n^2})$ = $8$ electrons. This formula can be used to determine the maximum number of electrons an orbit can hold.
Rule 2: The outermost shell's maximum capacity for holding electrons is 8.
Rule 3: The inner shells will be filled before the outer shells. The K-shell will be filled first, followed by the L-shell, and so on. As a result, electronic element configuration is done in ascending order.

Note:
Electronic Configuration aids in comprehending the periodic table's structure in relation to each element. It also aids in the comprehension and explanation of atomic chemical bonds. It describes the various properties and peculiarities of various elements. Electronic configuration, for example, explains why lasers and semiconductors have unique properties.