Teflon insulated wire

[Cloud 0]

Haha, the infamous electron configurations. Worked for a while, but once we touched on orbitals, everyone was either confused or mad about why we were basically lied to. The 2,8,8, etc explanation is extremely limited, just like the oxygen definition of oxidation. Works for the simple stuff, but insufficient once you touch on anything vaguely advanced.

 

yup. and i remembered seeing something like 2:8:18:2:6 in one of the text books back in secondary. then i asked my teacher why is it 18. she told me this u dun need to know. just know 2:8:8:2. i just went, orh. my mind says (u win liao).

[Stereo_Electronics 0]

Cloud: I see, no wonder you seem pretty pro in Chemistry

 

As for Oxidation,

Gain in Oxygen as oxidation is due to the fact that oxygen is very electronegative and it basically oxidises everything it reacts with.

It is the opposite for Hydrogen, with a oxidation number of +1 (other than metal hydrides).

For reduction, it is just the other way round.

 

So it is "kind of" correct but not proper. I learned this in Secondary school and I think they should scrap it man. Haha. It is not in the A levels chemistry, it is just loss/gain of electrons.

Btw, I have seen silk and cotton used as insulation. Anyone have experience with them?

 

Silk and cotton are commonly used in cables as vibration damping materials, helps in minimizing microphonics.

 

[ezzo 0]

yup. and i remembered seeing something like 2:8:18:2:6 in one of the text books back in secondary. then i asked my teacher why is it 18. she told me this u dun need to know. just know 2:8:8:2. i just went, orh. my mind says (u win liao).

 

Hahaha. Yeah, that is sufficient for O Levels actually, since we only need to know the 1st 20 elements, which will be up to a Electronic Configuration of 2, 8, 8, 2.

 

The actual filling up of energy levels are by:

1s

2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f

6s 6p 6d 6f

.

..

>with imaginary diagonal lines from the top right corner downwards of order of filling up (Sorry, cant draw out the lines) here.

 

So, the order will be 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p ...

where the number stands for the shell number and s/p/d/f are the orbital types. A s orbital can hold 2 electrons, p - 6 electrons, d - 10 electrons, f - 14 electrons.

 

For example, Ca with 20 electrons will have a EC of 1s(2), 2s(2), 2p(6), 3s(2), 3p(6), 4s(2), thus 2, 8, 8, 2.

While Sc, with 21 electrons will have a EC of 1s(2), 2s(2), 2p(6), 3s(2), 3p(6), 4s(2), 3p(1), thus 2, 8, 9, 2.

 

Okay, this is getting a little off..haha. Just for your info!

[nofing 0]

The orbital stuff with Hund's rule, the Pauli Exclusion Principle and what not is not very hard to understand. Don't understand why they won't just teach it in secondary school.

[Cloud 0]

i bet some of the better school will cover a little. esp when student asks and not brush off with things like: "you dun need to know." literally kill off any interest from the student.

 

now that they included semi-conductor in A lvl physics. i wonder how deep they willing to go.

Edited November 16, 2007 by Cloud

[ezzo 0]

Sorry to hear that Cloud, but I reckon it is probably your teacher?

My teacher back in Sec school did introduce my class to the spdf notation and I suspect probably only half the class got it. Hahaha. I mean it is there is no need to know about it and it might just confuse things for some people.

 

As about the Aufbau Principle, Pauli Exclusion Principle and Hund's Rule of Multiplicity (all being thought in A levels), judging by the syllabus of the O levels, there isn't much that can be applied with those principle, probably will be like overkill. Unlike in A levels where they are used in chemical periodicity.

 

HMMM. I happen to take the new A levels Physic and IMO, the topic on semi-conductors is pretty lame, seriously. There is only a few pages of notes on it and they do not related much to other topics (just like Nuclear Physics, Quantum Theory, etc etc...). I do not see a need to learn that in A levels.

Edited November 16, 2007 by ezzo

[Cloud 0]

hahah as usual. wat did they cover on?

pn junctions? intrinsic? or just stop at band gap?

[nofing 0]

Ezzo taking A levels too?

 

@Cloud: Yea Physics covers everything you mentioned and a little more including depletion region and doping.

 

[ezzo 0]

Hahaha.

there is band theory, intrinsic & extrinsic (n/p) semiconductors and semiconductor diodes

 

Yeah, you too nofing?

Actually, it is more of "took", haha.

Edited November 16, 2007 by ezzo

[milkpowder 0]

I did my A levels in the UK, but really don't think my syllabus had anything about semiconductors in it! We did the standard quantum stuff, eg wave superposition, two slit interference, quarks and bosons and other subatomic particles, etc... Sg A levels are probably much more advanced though. Honestly, I'd be lucky if I still remember any of it.

 

EDIT: actually band theory sounds very familiar. I remember it having to do with tubes:D

Edited November 16, 2007 by milkpowder

[ezzo 0]

milkpowder: Yeah! I heard from my friends, who went to UK after SG O Levels, that the A Levels there is...okay, simple or not, but to them, it was easy...

Edited November 16, 2007 by ezzo

[nofing 0]

That's why they do the June paper and we get the Nov paper. Wa think we can start another thread on education in Singapore at this rate.

[ezzo 0]

Hahaha. Yeah, this is going pretty off.

Na, its not really the June and Nov paper thingy. UK have a different syllabus requirements, just like many other countries which uses A levels, e.g. HK, Sri Lanka etc. The A levels here is "tailored" according to SG government requirements by Cambridge.

 

If we were rich enough, we could all go US/UK and get straight As.. LOL.

Edited November 16, 2007 by ezzo

[Cloud 0]

Hahaha.

there is band theory, intrinsic & extrinsic (n/p) semiconductors and semiconductor diodes

 

Yeah, you too nofing?

Actually, it is more of "took", haha.

 

thats quite alot. hmm not bad. sounds fun. i remember quantum was a joke. all they covered was photoelectric effect and nothing else. only when i went higher lvl than i realised there is alot more chim stuff in quantum. hahaha

[heady 0]

Guys it's great that you all can now discuss without getting too emotional. But can you do your discussion of physics in another thread please? This is so OT.

 

Edited November 16, 2007 by heady