Question

7. Compare and contrast Rutherford's model of the atom with Bohr's original model of the atom (4 points).

b) Compare and contrast Bohr's original model of the atom and the quantum mechanical model of the atom (4 points).

Answer 1

Rutherford's model v/s Bohr's model:

According to rutherford atom consists of a dense positive mass( later named as nuclues) at the center of the atom surrounded by the negative charge clouds or electron. This model do not say anything about the orbits of eletrons. But bohr proposed that electrons revolves around the nucleus in circular orbits which are qaintised. Each orbits energies and momentum are quantised.

Rutherford model did not explained the lie spectra but bohr used his model to explain the atomic line spectra of heated metals.

We can say that The Rutherford model suggested a new look into the nature of the nucleus, whereas the Bohr model suggested a new look into the mechanics of electrons.

Bohr's model vs Quantum mechanical model:

Bohr assumed electron as a particle which moves in a fixed orbit but Quantum model treated electron as a wave(for mathematical calculations) as well as particle.

Bohr propsed one dimensional model of atom which is characterised by a quantum no. n (principle quantum no.). 'n' describes the size of orbit. Whereas the quantum mechanical model proposed three dimensional model of atom, for which we need three quantum nos.(n,l,m), which describes the distribution of electron in the atom.

Bohr's model was failed to define Zeeman effect, stark effect etc while quatum mechanical model explains them correctly.

Bohr's model was unable to describe the spectra of larger atoms, while quantum model explains it.