Principal Quantum Number
| Formula / Notation | n = 1,2,3...; E_n = −13.6/n² eV (H) |
|---|---|
| Also Known As | Principal quantum number n, shell number, energy quantum number |
What is Principal Quantum Number?
The quantum number (n) that determines the energy level and size of an atomic orbital. Takes positive integer values (1, 2, 3...). Higher n values correspond to orbitals farther from the nucleus with higher energy. The principal quantum number is the most important factor in determining electron energy.
Formula & Notation
Other Names / Synonyms: Principal quantum number n, shell number, energy quantum number
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The quantum number (n) that determines the energy level and size of an atomic orbital. Takes positive integer values (1, 2, 3...). Higher n values correspond to orbitals farther from the nucleus with higher energy. The principal quantum number is the most important factor in determining electron energy.
The principal quantum number determines the energy and size of orbitals, explains the emission spectrum of hydrogen (Balmer, Lyman, Paschen series correspond to transitions to n=2, n=1, n=3 respectively), governs the number of subshells and orbitals per shell (n subshells, n² orbitals per shell), an…
No direct safety concern. Understanding principal quantum numbers helps explain why outer-shell (large n) electrons are more easily ionised (farther from nucleus, less bound), making large-n elements in Group 1 more reactive and more hazardous toward water and air.
The formula or notation for Principal Quantum Number is: n = 1,2,3...; E_n = −13.6/n² eV (H)