Difference between Bohr Model and Quantum Model
Niels Bohr proposed an atomic model to explain the drawbacks of Rutherford atomic model. The Bohr’s atomic model is also known as planetary model. Although the Bohr model does not perfectly describe the electronic configuration, yet it explains many concepts in a correct and simplified way. According to the Bohr model, electrons are subatomic particles that are present in orbits around the nucleus. On the other hand, the Quantum model describes the electrons as a wave. The Bohr model was concerned with size of the orbits only. In the Quantum model, the size of the orbit is described by principal quantum number. It is denoted as letter “n”. Hence we can say that the Bohr model was one dimensional model that used only single quantum number to describe the distribution of electrons in the atoms.
On the contrary, the Quantum model is a three dimensional model that use three different quantum numbers to describe the electronic configuration of atoms. The quantum model of atom was given by Schrödinger. He applied the de Broglie’s equation to the wave equation to describe the electronic configuration of atoms. The electronic configuration of an atom is the pattern of distribution of electrons in it. The Quantum model describes the electronic distribution of an atom by applying three quantum numbers. These quantum numbers are namely principal quantum number, angular momentum quantum number and magnetic quantum number.
The principal quantum number is concerned with size of the orbits. It represents the energy shells present around the nucleus. The main shells are namely s, p, d and f. The angular quantum number is related to the shape of the orbital. It is denoted by letter “l”. If l=0; the orbital has a spherical shape. If l=1; the orbital has polar shape and if the l = 2; the orbital is cloverleaf shaped. It goes on with shape being more complex with increasing the value of angular quantum number. The magnetic quantum number describes the orientation of orbital in space. The fourth quantum numbers satisfies the concept that no two electrons can have same sets of quantum numbers. It is referred to as spin quantum number.
The two models also differ from each other in pattern of energy distribution of electrons. According to Bohr model, energy of electrons is present in definite orbitals. Each orbital has a definite energy level. On the contrary, the Quantum model explains the energy distribution of electrons on the basis of probability concept. It does not explain presence of any definite orbital around the nucleus. According to this model, electrons can occupy a very close or far place in relation to the nucleus. It describes the orbits as a cloud of energy present around the nucleus while the Bohr model talks about presence of definite orbitals around the nucleus.
The Quantum model describes the electronic distribution of an atom in terms of its energy level, size, shape and orientation in space. According to this model, no two electrons can have the same set of all four quantum numbers.