Mendeleev · Science

Quantum numbers: labeling electronic states

Quantum numbers characterize electronic states in an atom. They do not describe a tiny planet on a classical orbit, but properties of quantum states.

Understand before calculating

Quantum numbers characterize electronic states in an atom. They do not describe a tiny planet on a classical orbit, but properties of quantum states.

Example

The numbers n, l and mₗ specify level, subshell type and associated spatial orientation; spin adds another quantum property.

The classic trap

Do not turn a model into a literal photograph of reality. Scientific models select particular properties to explain or predict a phenomenon; knowing their limits is part of using them correctly.

Understanding check

Explain the concept to someone who knows the periodic table but not this chapter. Then give one example and one situation where the most common shortcut would become misleading.

The numbers n, l and mₗ specify level, subshell type and associated spatial orientation; spin adds another quantum property.