K=2 ELECTRON, L=8 ELECTRON, M=18 ELECTRON, N=32 ELECTRON.
it is because each shell can contain only a fixed number of electrons, each shell is associated with a particular range of electron energy, and thus each shell must fill completely before electrons can be added to an outer shell.diff electron have different energy.

Structure of an Atom and Electron Shells

The structure of an atom consists of a central nucleus containing protons and neutrons, surrounded by a cloud of electrons. The electrons are arranged in specific energy levels or shells around the nucleus. Each shell can hold a specific number of electrons.

The K Shell
The innermost shell in an atom is called the K shell. It can hold a maximum of 2 electrons. The electrons in the K shell are closest to the nucleus and have the lowest energy level.

The L Shell
The next shell, known as the L shell, can hold a maximum of 8 electrons. This means that after filling the 2 electrons in the K shell, the remaining 6 electrons go into the L shell.

Octet Rule
The reason why the electron distribution follows a pattern where the first shell can hold 2 electrons and the second shell can hold 8 electrons is known as the Octet Rule. According to this rule, atoms tend to gain, lose, or share electrons to achieve a stable electron configuration similar to that of the noble gases.

Stability and Electron Configuration
Noble gases such as helium, neon, and argon have completely filled outer electron shells, making them highly stable. Other elements in the periodic table tend to undergo chemical reactions to achieve a similar stable electron configuration.

Electron Distribution
When an atom gains or loses electrons, it does so to achieve a complete outer shell. For example, an atom with 6 electrons in its outer shell will gain 2 electrons to achieve a stable configuration of 8 electrons, similar to the noble gas configuration.

Transition to Next Shell
Once the electrons in a shell reach their maximum capacity, any additional electrons are placed in the next available shell. This is why, after the K shell is filled with 2 electrons, the remaining electrons go into the L shell. Similarly, after the L shell is filled with 8 electrons, the next shell, M shell, can accommodate additional electrons.

Conclusion
The arrangement of electrons in different shells of an atom is based on the Octet Rule and the need to achieve a stable electron configuration. The maximum number of electrons each shell can hold determines the transition to the next shell. This electron distribution pattern helps atoms achieve stability and participate in chemical reactions to form compounds.