Discribe quantum mechenical model of atom

Quantum mechanics is based on a fundamental equation which is called Schrodinger equation. 

The solutions to this equation give the values of E and Ψ.

Solving the equation gives us many values of E. But out of these values, only certain solutions are permitted. Each permitted solution is highly significant as it corresponds to a definite energy state. Thus, we can say that energy is quantized.

Ψ gives the amplitude of the wave. All the information about the electron in an atom is stored in Ψ which is called its wave function.

But the square of the amplitude, that is, Ψ² gives us the region in which the probability of finding an electron is maximum. Ψ² is called probability density.

This region of space around the nucleus where the probability of finding an electron is maximum is called an orbital.In an atom a large number of orbitals are permissible. 

Each orbital is designated by a set of numbers known as quantum numbers