S

Shell

n=1,2,3,...; shell capacity: 2n² electrons
Quick Reference
Formula / Notationn=1,2,3,...; shell capacity: 2n² electrons
Also Known AsElectron shell, principal energy level, principal quantum shell

What is Shell?

An electron energy level or principal quantum shell, denoted by the principal quantum number n. Each shell contains one or more subshells (s, p, d, f). The first shell (n=1) holds up to 2 electrons; the second (n=2) holds up to 8; the third (n=3) holds up to 18.

Formula & Notation

n=1,2,3,...; shell capacity: 2n² electrons

Other Names / Synonyms: Electron shell, principal energy level, principal quantum shell

Properties & Characteristics

An electron shell (principal energy level) is a group of atomic orbitals with the same principal quantum number n. Each shell has a maximum capacity of 2n² electrons. Electrons in shells further from the nucleus have higher energy. The number of shells filled by electrons in an atom determines its period in the periodic table.

Uses & Applications

The shell model of electron configuration is used to explain the periodic properties of elements and their chemical behaviour. Shell filling order underpins the aufbau principle used to write electron configurations. Understanding shells is foundational for predicting bonding and reactivity.

Safety Information

Shell is a theoretical model with no direct safety implications. Understanding electron shells helps predict the reactivity of elements, particularly those with partially filled outer shells.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Shell
Formula n=1,2,3,...; shell capacity: 2n² electrons
Synonyms Electron shell, principal energy level, principal quantum shell

Frequently Asked Questions

An electron energy level or principal quantum shell, denoted by the principal quantum number n. Each shell contains one or more subshells (s, p, d, f). The first shell (n=1) holds up to 2 electrons; the second (n=2) holds up to 8; the third (n=3) holds up to 18.

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