Recently Added Formulas in Chemistry

· Electron Configuration
· Quantum Number
· Theory of Atom
· Atomic Number and Atomic Weight
· Orbit and Orbital

Additional Formulas

· Introduction (Atomic Structure)
· Atomic Number and Atomic Weight
· Theory of Atom
· Quantum Number
· Orbit and Orbital
· Electron Configuration

Current Location > Formulas in Chemistry > Atomic Structure > Electron Configuration

Electron Configuration

Each atom has a specific atomic structure depending on the number of electron present in atom. The distribution of electron in each atom is different and is called as electron configuration. It is controlled by three rules.

Auf-bau principal
Hund’s rule
Pauli’s principal

Auf-bau principal: Electrons in an atom first enter into lowest energy orbital and then enter into high energy orbital step-wise. This type of arrangement of electrons is known as Auf-bau principle. The order of energies of the orbital is s < p < d < f.

Pauli’s principle: It is based on the fact that no two electrons in an atom can have the same set of four quantum numbers or any orbital in an atom can not accommodate more than two electrons.

Hund’s Rule: It explains that electrons occupy orbital of equal energy such that maximum possible number of electrons remains unpaired and their spins remain parallel. This is called as Hund’s rule of maximum multiplicity.
Paired electrons – Two electrons with opposite spins in an orbital is called paired electrons.
Unpaired electrons – One electron in an orbital with spin only in one direction is called unpaired electrons.