Fig. 2.1 Electron configuration of silicon atom
The distribution of electrons in the various orbits for Silicon and Germanium atoms is shown in Table 2.1 and in Figs. 2.1 and 2.3.
Table 2.1
Element | Atomic number (Z) | Configuration |
---|---|---|
Silicon (Si) | 14 | 1s2 2s2 2p6 3s2 3p2 |
Germanium (Ge) | 32 | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p2 |
Electron configuration of Silicon atom (Fig. 2.1)
Silicon atom representation as a tetravalent material is shown in Fig. 2.2 as a basis to understand the concept of covalent bond formation etc. Silicon semiconductor, as a ‘Tetravalent’ material, has ‘four valence electrons’. The force of attraction between the nucleus (core) and the electron inside the atom is given by
where electronic charge q is in coulombs, r is the separation distance between electrons and nucleus (in an atom) in metres, the force F is in Newtons, ɛ0 is the permittivity of free space in farads/metre, and permittivity of the free space ɛ0 = 8.849 × 10–12 farads/metre.
Fig. 2.2 Representation of silicon atom with its valence electrons
This force of attraction F between the nucleus and the electron is counter balanced by
where m is the electronic mass, m = 9.109 × 10–31 kg, v is the speed of the electron in the orbit, acceleleration a = v2/r and is directed towards the nucleus.
The potential energy PE of the electron at a distance ‘r’ from the nucleus
According to the conversation of energy, energy associated with the electrons W = Kinetic energy + Potential energy:
where the energy W is in joules.
Substituting the value
Equation (2.4) shows the relation between the radius r (distance of electron in the circular orbit from the nucleus) and the energy W of the electrons. It also shows that the energy of the electron becomes less (i.e., more negative) as it approaches closer to the nucleus. The relation is given by Eq. (2.4A):
where n = 1, 2, 3 and so on.
Humankind has become extremely dependent on electricity, without it we can’t run the household, keep…
[1] Define the term synchronous speed [Dec-2003] For synchronous machines there exists a fixed relationship…
We shared a lot of interview questions on electrical machines, power system and power electronics. Today we…
DIESEL POWER STATION A generating station in which diesel engine is used as the prime…
Q:Why syn. generators are used for the production of electricity? A:synchronous machines have capability to…
Hydro-electric Power Station A generating station which utilises the potential energy of water at a…