Physic Labs

Physical chemistry

Atomic structure

From the Bohr model to quantum orbitals, quantum numbers and electron configurations explain periodicity.

The Bohr model gives discrete energy levels for hydrogen; quantum mechanics replaces definite orbits with wavefunctions and probabilities.

Quantization and orbitals

From the Bohr model to quantum orbitals, quantum numbers and electron configurations explain periodicity.

Definition: Core definition

An orbital is a one-electron spatial state described by a wavefunction; |ψ|² is probability density.

n=1,2,…;l=0,…,n−1;ml=−l,…,l;ms=±12n=1,2,\ldots;\quad l=0,\ldots,n-1;\quad m_l=-l,\ldots,l;\quad m_s=\pm\frac12

Example: Worked example

Apply the model to a simple case: For n=2 there are 2s (l=0) and 2p (l=1); p has three m_l values and holds at most six electrons.

Solution

For n=2 there are 2s (l=0) and 2p (l=1); p has three m_l values and holds at most six electrons.

An orbital is a one-electron spatial state described by a wavefunction; |ψ|² is probability density.

Quantization and orbitals
QuantityModel / rule
Key relationFrom the Bohr model to quantum orbitals, quantum numbers and electron configurations explain periodicity.
Meaning / useFor n=2 there are 2s (l=0) and 2p (l=1); p has three m_l values and holds at most six electrons.

Which quantum number specifies an electron shell and its characteristic size?

Which statement best matches the model described?

References

  1. H. Haken and H. C. Wolf (2005). Atomic Physics