# Shell and Subshell Simple Explanation

## What is a shell in chemistry?

SHELLS

Electrons revolve around the nucleus in a particular circular pattern known as the shell of an atom.

The electron shell is also known as orbit or energy level.

## Shell Representation

It is denoted by n. Where n is any positive integer.

Each shell has a fixed amount of energy.

n=1 is known as K-Shell

n=2 is known as L-Shell

n=3 is known as M-shell

## Finding the maximum number of electrons in any shell Formula

The maximum number of electrons in any shell can be found by using the Bohr filling formula=2n2

## What is meant by sub-shells?

SUB-SHELLS

A shell or energy level is further divided into sub-shells. A subshell is defined as ( The region where the probability of finding an electron is maximum in the orbit is termed as a subshell.) The n value of a shell is written before the symbol of a sub-shell.

## EXAMPLES

• For n=1, K-shell contains only one sub-shell 1s
• For n=2, L-shell contains two sub-shells represented as 2s,2p
• For n=3, M-shell contains three sub-shells represented as 3s,3p,3d
• For n=4, N-shell contains four sub-shells represented as 4s,4p,4d,4f

## Maximum electrons in a subshell

• S subshell can accommodate a maximum of 2 electrons
• P subshell can accommodate a maximum of 6 electrons
• D subshell can accommodate a maximum of 10 electrons
• F subshell can accommodate a maximum of 14 electrons

Distinguish between shell and subshell

## Q.What are energy shells in chemistry?

There is a specific amount of energy tied to the energy shell. The energy associated with an orbit increases with the orbit’s separation from the nucleus. The energy level is also the name of these shells.

## Q.How many subshells are there in N subshell?

The number of sub-shells within a shell = “n” value.

It indicates that there are four subshells named 4s,4p,4d, and 4f for the N shell.

## Q. Provide notation for subshells of M shell?

The number of sub-shells within a shell = “n” value.

It indicates that the M shell has three subshells designated 3s, 3p, and 3d.

## Q.State Aufbau principle.

AUFBAU PRINCIPLE

Named after the German phrase “Aufbau,” which means “to build up,”

According to the Aufbau principle, electrons will first occupy lower-energy orbitals before moving on to those with higher energies.

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