Question

Explain the position of electrons based on the modern revised model of an atom.

Answer 1

Step 1: Proposals of Neil's Bohr (Bohr's Postulates):

1. In the hydrogen atom, there is a single electron which can revolve around the nucleus in certain definite orbits known as stationary orbits. In a stationary orbit, the electron has an angular momentum $L$ which is an integral multiple of $\sout{h}=\frac{h}{2\mathrm{\pi }}$ where $h$ is Planck's constant, i.e., $L=\frac{nh}{2\mathrm{\pi }}=n\sout{h}$, where $n$ is known as the quantum number, and its possible values are $n=1,2,3,$ etc. This equation is known as Bohr's quantum condition. The electron in this case is in a stationary state.
2. When the electron revolves in a stationary orbit, it does not emit electromagnetic radiation as predicted by the electromagnetic theory of light.
3. The emission of electromagnetic radiation from the hydrogen-like atom takes place when the electron makes a transition from one stationary orbit to another. If the transition is from an orbit of higher energy $E_2$ to an orbit of lower energy $E_1$, then the energy $h\nu$ of the emitted radiation, according to Planck's law, will be $h\nu =\sout{h}\omega =E_2-E_1$, where $\nu$ is the frequency of the emitted radiation; $\omega =2\mathrm{\pi \nu }$ is the angular frequency. This equation is known as Bohr's frequency condition.

Step 2: Position of electrons based on the modern revised model of an atom:

1. The electrons inside atoms are placed in discrete orbits called stationary orbits.
2. Electrons can jump to higher levels by absorbing energy and move to lower energy levels by losing or emitting their energy.
3. As long as, an electron stays in its own stationary orbit, there will be no absorption or emission of energy.
4. Electrons revolve around the nucleus in these stationary orbits only.

Hence, the position of an electron according to the modern revised model of an atom is an electron revolves around a nucleus at different energy levels at a specific fixed distance from the nucleus.