Electronic Devices - Semiconductors - Discussion

Discussion Forum : Semiconductors - General Questions (Q.No. 12)
12.
Effectively, how many valence electrons are there in each atom within a silicon crystal?
2
4
8
16
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
32 comments Page 1 of 4.

Krishnakumar said:   1 decade ago
Regular arrangement of atom to form a systematic structure is called crystal. Here they are menstioned as si crystal. so it should be stable. for stable atom the outermost orbit contains 2 or 8 or 8 or 16 or 32... here atomic no. of si is 14. so it has three orbits (2,8,4). it should be stable so it become 2,8,8. hence the valence electron of si crystal is 8

DURYODHAN said:   1 decade ago
The question asked is for crystal but not for an atom. So, Si crystal has 8 valence electrons I agree with 8.As we all know that a single si atom has 4 valence electrons in valence orbit. the covalent bonding is done between 4 same si atom by sharing one electron from one atom.
4 valence electrons + 4 shared(1+1+1+1)=8 electrons

Chaitra said:   1 decade ago
When many atoms are combined, i.e in a silicon crystal, each atom of Si is surrounded by many other atoms.

Thus each atom will take 4 electrons from neighboring atoms, and share. So in all, even though a single atom has 4e, BT when atom is made to exist in crystal, it has 8 electrons.

Anshu said:   1 decade ago
Every si atom has 4 valence electrons but, Here we are talking about 'crystal' which is a crystalline structure of si atom in which si makes bonding with their neighbouring atoms and shares their valence electrons.

So, 4(own valenc e) + 4(shared e) = 8.

Dharmendra kumar said:   1 decade ago
Yes its about the silicon crystal, not about the single silicon atom.

As an atom of silicon has 4 valence electron in its outermost shell. So its can make other 4 electron to make covalent bond and form a crystal. Hence its answer is 8 not 4.

Mani said:   1 decade ago
As we all know that a single si atom has 4 valence electrons in valence orbit. the covalent bonding is done between 4 same si atom by sharing one electron from one atom.
4 valence electrons + 4 shared(1+1+1+1)=8 electrons

Neeti said:   1 decade ago
Si atom has 4 electron, but when we talk about Si crystal it means many Si atoms packed together, thus they form covalent bond for becoming stable. Thus there are 8 electrons in outer valence band.

Atish said:   7 years ago
As we all know that a single si atom has 4 valence electrons in valence orbit. The covalent bonding is done between 4 same si atom by sharing one electron from one atom.

So 4valance+4 shared = 8.
(1)

Hariom said:   1 decade ago
@prithvi

Si have 4 electron in it's outer most orbit and these 4 electrones will form covalent bond with the 4 neighbouring Si atom thus each Si atom in the crystal will now have 8 elctrones.

Raju anand said:   1 decade ago
Silicon atom have tetravalent atom and its belong to p block so it form four covalent bond and contain eight electron in outermost orbit so that they achieve inert gas structure.


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