Structure of Atom
Subatomic Particles : Discovery and Characteristics
-
Macroscopic objects have particle character, so their motion can be described in terms of classical mechanics, based on Newton’s laws of motion.
-
Microscopic objects, such as electrons, have both wave-like and particle-like behaviour, so they cannot be described in terms of classical mechanics. To do so, a new branch of science called quantum mechanics was developed.
-
Quantum mechanics was developed independently by Werner Heisenberg and Erwin Schrodinger in 1926.
-
Quantum mechanics takes into account the dual nature (particle and wave) of matter.
-
On the basis of quantum mechanics, a new model known as quantum mechanical model was developed.
-
In the quantum mechanical model, the behaviour of microscopic particles (electrons) in a system (atom) is described by an equation known as Schrodinger equation, which is given below:
Where,
= Mathematical operator known as Hamiltonian operator
ψ = Wave function (amplitude of the electron wave)
E = Total energy of the system (includes all sub-atomic particles such as electrons, nuclei)
-
The solutions of Schrodinger equation are called wave functions.
Hydrogen atom and Schrodinger equation
-
After solving Schrodinger equation for hydrogen atom, certain solutions are obtained which are permissible.
-
Each permitted solution corresponds to a definite energy state, and each definite energy state is called an orbital. In the case of an atom, it is called atomic orbital, and in the case of a molecule, it is called a molecular orbital.
-
Each orbital is characterised by a set of the following three quantum numbers:
-
Principal quantum number (n)
-
Azimuthal quantum number (l)
-
Magnetic quantum number (ml)
-
For a multi-electron atom, Schrodinger equation cannot be solved exactly.
To view the complete topic, please