about -4:10, this vid says "Each atom has four valence electrons. In the outer ring, they share four atoms with other atoms for a total of eight valence electrons."
https://www.allaboutcircuits.com/video-lectures/semiconductor-theory-intrinsic-semiconductors/

Confusing-- atoms share atoms with other atoms?

Also, he says the crystal atoms have 4 valence electrons, but they look like they have 5 valence electrons.

 

So what do you think is really going on?

 

i don't want to guess wrong, cuz someone will insult me.

also, i don't understand how the middle atom can have 8 electrons and be the same type of atom as the others, which seem to have 5. Maybe the image doesn't show their other electrons.

Unless, oh, maybe the 4 atoms shown could be the outer atoms, which he says have fewer electrons, since they don't neighbor atoms. In which case, he could have just said "these are the outermost atoms, which have fewer electrons", instead of hand-drawing red circles to represent more atoms.

also, he says 4 are shared, but in the picture all 8 appear to be shared.

also, the slide says "covenant bonds", but the narrator says "covalent bonds". Maybe i'm mis-hearing.

 

1) Atoms "share" electrons. Sharing atoms is a non sequitur.
2) Forget about valence bond theory and ionic bonds, think "molecular orbitals."
3) So the speaker seems to have misspoke. Big deal? It was clear in context.

 

I just wanted to know if you knew anything about chemistry. Since your knowledge of Chemistry appears to be limited, I'll stick to the specific issue. The statement should be "atoms share electrons with other atoms". In a pure slab of Silicon (Si), those Si atoms have an outer shell that holds four electrons. Quantum mechanically the shell can hold a maximum of 8 electrons. In a crystal lattice of Si atoms, which electrons belong to which atoms is a fluid situation, they are not bound in the sense that planets are bound to a star. Electrons in outer shells are allowed by Quantum Mechanics to be here, there, and everywhere so to speak. Similarly in a metal, the outer shell will hold a single electron. The freedom of this outer electron is why we have current flow in metals. Those electrons are very loosely bound to the nearest nucleus, and they have sufficient energy to move about with very little encouragement. A potential difference of 1 volt will move a considerable number of them.

What makes semiconductors interesting is the introduction of impurities from group III and group V. Group III and Group V are columns on the periodic table of the elements. What these impurities do is alter the behavior of the crystal lattice by adding (Group V) and additional electron, or subtracting (Group III) an electron (creating a "hole"). The former process creates an n-type semiconductor, and the latter process creates a p-type semiconductor. Now in the two kinds of material we have two different kinds of current carriers. We have electrons from the Group V impurity, and we have holes from the Group III impurity.

WRT "covenant" and "covalent" we have a simple typographical error that you should be able to resolve. Since covalent refers to a bond that is achieved by sharing electrons and covenant is a contract between two parties. Which of those two words is a better fit for the context? The authors are probably grateful for the corrections; but I seriously think that such mistakes should not be a big deal, or lead to the level of confusion that you profess.

 

This isn't a complaint, just a suggestion that whomever manages these pages could mention the errors in the page. The page text does seem to avoid some of the errors, but i come for the videos. No place does it say "Corrections".

Multiple errors in the slide text, images, and spoken content on just one video is surprising i must say, and doesn't reflect that well on this website. But hey, it's free.

When learning new material, i'm not going to make any assumptions. In this case, it seems i was lucky enough to figure out what was meant, but in more advanced topics i might not know what's correct and what's an error. On the other hand, that makes it a good learning challenge Not really, it just means i don't trust any of the info in these videos.

Thx for the detailed explanation about the chemistry, but that's not the point, especially if you do so begrudgingly while making me feel like i'm the one who's in the wrong here. i won't have you next to me explaining everything as i watch the videos (wait, are you offering? . Putting corrections on the video pages would be more helpful to the general audience. "I'll stick to the specific issue" -- You went beyond the the specific errors mentioned, and beyond content of the whole video, that's sticking to the specific issue? Goodness how much more would you have written. I'm impressed with your knowledge, maybe you should make some videos.

Forget about valence bond theory and ionic bonds, think "molecular orbitals."

so basically, don't watch this video.

Nobody mentioned whether 8 are shared (as shown in the picture) or 4 are share (as the narrator states).

cheers

 

Nobody mentioned whether 8 are shared (as shown in the picture) or 4 are share (as the narrator states).

cheers

Perhaps each atom shares its 4 electrons. In this example, both are true. There are 8 electrons total shared, and each atom shares its 4 electrons. The net charge must be neutral in this example. It seems you need to concentrate on the context and not try to find confusion in the wording.

 

You can try putting carts before horses, buy it doesn't usually work out so well. My point is that many people do circuits without understanding semi-conductor physics. People that understand semi-conductor physics are often lost when it comes to the practical applications of electronic circuits. If you can't unscramble simple malaprops and typographical errors you might want to fall back a bit.

 

Perhaps each atom shares its 4 electrons. In this example, both are true. There are 8 electrons total shared, and each atom shares its 4 electrons. The net charge must be neutral in this example. It seems you need to concentrate on the context and not try to find confusion in the wording.

Great, that helps me understand . thanks

I'm not "trying to find" confusion.

these mistakes are inexcusable. From a college prof no less .

If you can't unscramble simple malaprops and typographical errors you might want to fall back a bit.

And you apparently can't understand logical reasoning . If this relatively basic vid contains multiple mistakes, one can infer the other videos do as well, and the other mistakes might not be apparent .

Also, if you're coming onto this electronics education website telling people they shouldnt learn electronics, you might want to fall back a bit.

 

You are going to be very hard pressed to find anything that's longer than a few pages or few minutes that doesn't have mistakes in it. Gotta get used to it. I long since lost count of how many "professional" things I've seen that had what appeared to me to be glaring errors in them, including highly-polished and heavily-reviewed items put out by major ad agencies. I know that the video lectures I've put out on Coursera and the Technical Articles I've written for AAC have some errors in them. I know my PhD dissertation has some errors in it. I would not be surprised to discover that every paper I've ever had published had at least one error in it (I know that few of them do, but there's some hope that a few of them are actually clean). I remember sitting in my surgeon's office waiting for him to come in and in five minutes I found three errors on this professional BMI chart he had posted on the wall. I've seen numerous billboards with spelling errors and wonder how someone about to spend that kind of money can't manage to have the copy proofed better than that. Then there's all the CD/DVD/BD covers I've seen (and/or the disk content itself) that has glaring errors and you wonder how they don't check something closer when they know they are about to make millions of copies of it. Yet it happens and it happens because humans are involved and the sad fact is that people working on a project for more than a short period of time start to see what they know should be there and not what is actually there.

 

You are going to be very hard pressed to find anything that's longer than a few pages or few minutes that doesn't have mistakes in it.

lol
This aren't CD liner notes. Science and electronics are kinda technical. The bar for correctness is reasonably significantly higher. These are electronics tutorials. On an electronics education website. Taught by a college prof. Well ok, North Seattle Community College, but still.

Mistakes happen, sure, but if an electronics prof can't spell "covalent"-- even as he's underlining the word with his mouse, no less. No words. But hey, i've seen more than one post by EE students complaining they can't understand their electronics prof's thick Asian accents, so i guess this is an improvement.

How many pages is your PhD dissertation? This video is only a few minutes long. It's not a student's work.

You're right, there's a lot of sloppy work, by people who have low standards of excellence. Having worked in numerous top American corporations, i've seen engineers who don't know their knee from their elbow get promotions and raises. American mediocrity at it's finest. And people excuse it.

 

You are going to be very hard pressed to find anything that's longer than a few pages or few minutes that doesn't have mistakes in it. Gotta get used to it. I long since lost count of how many "professional" things I've seen that had what appeared to me to be glaring errors in them, including highly-polished and heavily-reviewed items put out by major ad agencies. I know that the video lectures I've put out on Coursera and the Technical Articles I've written for AAC have some errors in them. I know my PhD dissertation has some errors in it. I would not be surprised to discover that every paper I've ever had published had at least one error in it (I know that few of them do, but there's some hope that a few of them are actually clean). I remember sitting in my surgeon's office waiting for him to come in and in five minutes I found three errors on this professional BMI chart he had posted on the wall. I've seen numerous billboards with spelling errors and wonder how someone about to spend that kind of money can't manage to have the copy proofed better than that. Then there's all the CD/DVD/BD covers I've seen (and/or the disk content itself) that has glaring errors and you wonder how they don't check something closer when they know they are about to make millions of copies of it. Yet it happens and it happens because humans are involved and the sad fact is that people working on a project for more than a short period of time start to see what they know should be there and not what is actually there.

Bravo for making those points. Since most of my background is in the software and embedded systems business I'll offer two more data points. First, getting a PC board layout correct on the first shot is a very rare occurrence. In some cases the cost of turning a board is smaller than the redundant checking especially as the salaries of those tasked with the checking goes up. Second, no piece of software or firmware that I ever produced, was correct after the first clean compile. The process of stepwise refinement goes on for months after the the first run. My last project was over three years to completion and the build numbers went from 1 to 2347. Management changes and revised requirements had a lot to do with those results. That I am not an audiophile may have also been related to the difficulties, since they have a good deal of trouble defining precise requirements. Writing firmware is not something you can do by ear.

 

getting a PC board layout correct on the first shot is a very rare occurrence.

right. That's why you check your work, review, correct, revise. You're saying people should release their first shot as-is?

 

If you have just now realized that most of life and knowledge is (coarse language removed).......you're welcome.

 

Science and electronics are kinda technical. The bar for correctness is reasonably significantly higher...

To quote The Princess Bride:
"Get used to disappointment."

You're right that if there are known errors it's worth trying to correct them, but there's no point getting on a high horse about it. Mistakes happen everywhere. I'm sure you've made some too, probably even in technical fields.

 

thx to everyone for the life advice. LOL. too funny. i thought i came here for electronics info, and instead i get pseudo-philosophical excuses for errors.

Get used to critiques from people who's standards aren't as low as yours. Or don't get used to it, just expect it.

there's no point getting on a high horse about it. Mistakes happen everywhere. I'm sure you've made some too, probably even in technical fields.

i'm not getting on a "high horse", i'm reporting errors in website content so the maintainers can, maybe, alert future visitors, to improve the learning experience.

And of course i've made mistakes, plenty. I try not to make excuses, or tell people "that's life." I try to correct the mistakes.

 

right. That's why you check your work, review, correct, revise. You're saying people should release their first shot as-is?

Not remotely am I saying that. Is English your second language?

 

Not remotely am I saying that. Is English your second language?

no, i stopped at "getting a PC board layout correct on the first shot is a very rare". I see now your point was you go through a very extensive review and revise process, which is great! So i guess you're agreeing with my critique of the toot.

That I am not an audiophile may have also been related to the difficulties, since they have a good deal of trouble defining precise requirements.

Unclear. Sounds like two separate issues.

Writing firmware is not something you can do by ear.

If it's audio firmware, then ears are involved, no? What kind of product? That's cool, i'm working on an audio product too. So you made the boards and the firmware?

(bracing myself for a hostile reply

 

Welcome to the weird word of quantum physics, it just keeps getting weirder and weirder, and you might have thought God didn't have a sense of humor.

I swear it is beginning to resemble magic with some of the developments. I consider myself a science buff and I am enjoying the show.

 

no, i stopped at "getting a PC board layout correct on the first shot is a very rare". I see now your point was you go through a very extensive review and revise process, which is great! So i guess you're agreeing with my critique of the toot.


Unclear. Sounds like two separate issues.


If it's audio firmware, then ears are involved, no? What kind of product? That's cool, i'm working on an audio product too. So you made the boards and the firmware?

(bracing myself for a hostile reply

The company was Wadia and they make CD players and DACs.
www.wadia.com
Yes I did several boards, and quite a bit of firmware.