MCQ Detailed View

In chemistry, many principles and rules are named after the scientists who discovered them or first explained them. For example, the Pauli Exclusion Principle is named after the Austrian physicist Wolfgang Pauli, who proposed that no two electrons in an atom can have the same set of four quantum numbers. This principle explains electron arrangements in orbitals and is fundamental in quantum mechanics.

Similarly, Hund’s Rule is named after Friedrich Hund, a German physicist. This rule states that electrons fill degenerate orbitals (orbitals of the same energy) singly first, before pairing up, to maximize stability. It explains why certain electron configurations are more stable than others.

Le-Chatelier’s Principle is named after Henry Louis Le Chatelier, a French chemist. This principle describes how a system at equilibrium responds to external changes in concentration, pressure, or temperature. It is widely used in chemical equilibrium and industrial chemistry applications.

On the other hand, the Aufbau Principle is different. The word “Aufbau” is derived from the German word meaning “building up” or “construction”. It is not named after a scientist. Instead, it describes the method of building up the electronic configuration of atoms by filling orbitals in order of increasing energy levels (1s → 2s → 2p → 3s → 3p, etc.). The principle provides a guideline for predicting electron arrangements, but it is not credited to any single scientist.

Therefore, among the given options, the only principle not named after a scientist is the Aufbau Principle. This distinction makes it important for students to remember which scientific laws honor individuals and which are general conceptual terms derived from language.