Hybrid Orbital Theory : Overcoming the Limits of Atomic Orbitals Early atomic orbital models could not explain real molecular shapes. For example, methane should show 90° bond angles, but experiments reveal 109.5°. Hybrid orbital theory solved this by combining s and p orbitals, explaining bond angles, directionality, and molecular geometry more accurately. Simply add : […]
From Hertz to Einstein: The Discovery of the Photoelectric Effect The photoelectric effect was first observed by Heinrich Hertz in 1887 when he noticed that ultraviolet light caused sparks to jump more easily between metal electrodes. Later, Wilhelm Hallwachs and Philipp Lenard confirmed that light could eject electrons from metals. While classical wave theory could
Birth of Avogadro’s law In 1811, Italian scientist Amedeo Avogadro proposed a hypothesis that would later become known as Avogadro’s Law. At the time, scientists struggled to explain the relationship between the volume of a gas and the number of particles it contained. Avogadro suggested that equal volumes of all gases, at the same temperature
Birth of Charles’s Law In the late 18th century, French scientist Jacques Charles conducted experiments to investigate how the volume of gases changes with temperature. While flying hot air balloons, Charles observed that gases expand when heated. His careful measurements eventually led to the formulation of what we now call Charles’s Law, which describes the
Birth of Boyle’s law In the mid-17th century, Irish scientist Robert Boyle conducted a series of experiments to investigate the behavior of gases. Working with Robert Hooke, he discovered a consistent relationship between the pressure and volume of a gas at constant temperature. In 1662, this observation was formally published, becoming what we now call
What is Aufbau principle? S P D block Let’s look at the periodic table according to the period. From the first period, the electron is piled up.
1925 Wolfgang Pauli One of the most fundamental principles in quantum chemistry and atomic structure is the Pauli Exclusion Principle, formulated by Austrian physicist Wolfgang Pauli in 1925. This principle is crucial in explaining the electronic structure of atoms, the arrangement of electrons in orbitals, and ultimately the behavior of matter at the microscopic level.
What is Hund’s Rule? Imagine you get on a bus, and there are plenty of empty seats. Most people prefer to sit alone, leaving an empty seat between themselves and others. We naturally avoid sitting right next to someone when there’s space elsewhere. This is a simple way to understand Hund’s Rule in chemistry. Hund’s
