Groups of the Periodic Table

[TheCheeseinacan]

You are an absolute legend! Great videos, thanks :)

[tiearruda]

lol halogen lamps, that is no mistake.. thanks for the video!!

[ERIK31351]

8 isn't the magic number, it could also be 2. And hydrogen can't get 8 electrons and it doesn't need them, it just needs two! You have no idea what your teaching.............

[someone20ify]

@ERIK31351 i know he was wrong in some parts!!!...but still he can explain very well and he can teach alot of subjects so he is a genius

[satisfiction]

caveat... had to look that one up. I love you Khan.

[TheCanadiangirl95]

He is so concerned with not offending any metals, what a sweet guy ;)

[sugarhon3yic3t3a]

gold is the best conductor not silver

[MediumNothinFull]

i can totally answer your 8 question dude

[Do0odiie]

I love the way you teach , I'm planning to study pharmacy and chemistry is important for such a major and you're literally saving my life with these videos .. thank you big time :)

[goldensilverstar]

what the fuck is aloooominum? .....its al-a-minium......fucking freshy cunt

[mjvirock]

@goldensilverstar stfu dumb bitch your not cool.

[someone20ify]

@goldensilverstar ehhehe u better check the word again on dictionary!!....it is aluminum...so he said right...ehhe shame on u!!!

[goldensilverstar]

Where is the fuckin calculations, fuck u all u uneducated cunts

[ridjen]

@goldensilverstar oh dont act stupid everyone knows what hes talking about you "cunt"

you have some real nerv -_____-

[2001cats]

What do you record with?

[manalexxxx]

i can see the natural force when i look at that table, looks like a rainbow, it is a system. it is matrix.

[pspblackhorns2k8]

is there a tutorial where i can learn how to find the group and period of a element

for example :11 na = 1s2 2s2 3p6 3s1 then the next step of that i forgot can someone here help me please..

[MollyNovak]

For once, youtube helps me do my homework

[Jonathanvang14]

@MollyNovak

[Jonathanvang14]

@Jonathanvang14 i know me too

[sharkh4xor]

thanks sal :)

[putumban96]

Doesnt chromium and copper have 1 electron in their outer shell??? i searched for it on google and on all the periodic tables i find there it says that chromium and copper have 1 valence electron

[Spacehorse99]

@putumban96

idk ask your teacher

[truebestfrenz123]

@putumban96  rememeber it's a transition metal so i guess it doesnt have to have one alone

[01rai01]

its Aluminium, whats wrong with you people

[davidszilvasi]

bitches.... it's the curriculum at the 7th class!!!!! HOW COULD IT BE THAT SOMEONE DOESN'T KNOW THIS????????????

[Spacehorse99]

@davidszilvasi

STFU ASSHOLE

[streetpartying]

@davidszilvasi feel special yet?

[Harrisam66]

It is stated that silver is the best conductor of electricity. If this is so then why are circuitboards and expensive wire contacts plated in gold? My understanding was that the more expensive gold was used because it was a more superior conductor. Perhaps silver corrodes too easily?

[theprettygirl45]

He is a great professor, but I'm sill confused about some things. I don't know how many electrons an element needs to get 8. Confusing! I have a test tomorrow on this.

[Kdubz2828]

these metals say' hey, take my electrons" haha :)

[HotManies]

Does 9H have to watch this video??

[THEBLACK493]

CAN SOMEONE TELL ME HOW IONISATION AND ELECTRON GAIN ENTHALAPY DIFFER IN THIS TABLE ALONG THE ROUP...AND ALONG THE PERIOD...

i am much confused in ege...

[DalaDos28]

someone is very stupid

[TishyTasha12]

@DalaDos28 you?

[requshei]

I don't get it.. How does an atom gaining just one electron change when the nucleus still need extra neutrons and protons?? Or is this guy just talking strictly about electrons and will get to the nucleus soon...?

[ainulsyahirah09]

great !!..can revise me sometimes..

[OscillatingRhythms]

@10minutes 39secs. You say that Krypton's outermost shell is 3s2 3p6...It is, of course, 4s2 4p6. You might want to add a note to avoid confusion. Great videos...keep up the great work.

[crudeoilsystems]

Excellent tutorial

[sadhana96]

Ya u were

[leakedazaz]

my teacher asked for what element is in period 4, group 5, i said V he said AS, was i wrong?

[skwaag5233]

a balloon exploding in a children's party....that's a fun thought :) Great videos Kahn. You're really helpful

[paulcen]

because helium is a noble gas! and its very unreactive and its very unlikely to explode... at a childs birthday party... you sir, have just taught me and made me laugh at the same time!

[purpleleach1]

Even though Helium is a noble gas, in stars, could it bond with other elements like hydrogen?

[xAndii92]

I'm a bit confused. You said the transition metals are really good conductors because they have a surplus in electrons. And you said Silver is the best conductor. But Al has 3 electrons (more valance electrons than Silver) Wouldn't that mean Al would be a better conductor than Silver? Could someone explain?

And one more question, to calculate the outer shell, do you just add all the sub-shells? E.g 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6. The outer shell for this is 8 right? Or 6?

Thanks

[skwaag5233]

@xAndii92

Silver has more electrons in the d and f orbitals of such and so it has alot more atoms to spare and thus is more reactive.

you add up the electrons in the outer most shells. In this example it would be period 4. You have 4s2 and 4p6. 6+2=8.

Hope this helps :)

[IBMua]

10:40 4s2 4p6, not 3s2 3p6. =)

[memoriedream]

This is sooo helpfull thank you so mucyou sound so young. Not like a voice of someone i expect to know all about this and know how to explain it

You have a good way of saying things,

[pooppeeyoupants]

but u helped me learn why and how each group is sorted! Thx man. :D

[mikolchung]

Helium is very unlikely to explode at a child's birthday party. haha- I hope that shows up on my MCAT. Thanks Sal!!

[Atlaswolves]

Can i call U Teacher? Cos u are real good.

[paulceltics]

1 full day of Khan Academy > 1 1/2 semester of enr. chem

[Darkcurse101]

@paulceltics yeah man, I was thinking about that, too! xD

[purpleleach1]

@Darkcurse101 I took honors chemistry sophomore year of highschool, we learned about valence electrons but I definately did not learn as much as this guy is teaching in just these couple of videos. I've probably learned more in these first several videos than I did 1rst semesters of honors chemistry. I had a terrible teacher though (Note: Teacher got fired my junior year for being late to class a lot).

[narcomanel]

Well, why is it that on every site I search silver's configuration ends with 5s1, but here it ends with 5s2?...

[lalarizo]

gold 

[lalarizo]

i think that gold is the best electricity conducter on earth

[BigC4god]

no life

[ullasrajchellappan1]

You are doing such a great service to humanity...no kidding!!!!!!!!!!!!

[verymetal86]

hey man, another great teacher ! I started watchin markrosegarten last nite, and though...this fella's a bloody great tutor, but, holy shite! you are excellent too! You sound like jello biafra as well! the dogs bollox man !

[MrMcdagy]

can you please explain the contradiction between hydrogen not wanting to give away its electron like mentioned at 1:50 when on the other hand its described pretty reactive like in 11:20 

[fongg2]

@MrMcdagy Yeah, that's what I thought was strange as well... Could somebody explain this please? And why is Helium a noble gas? Since it only has 2 electrons in its outer shell... Must be an exception?

BTW, THANKS a lot Khan Acadamy! I never really understood the periodic table and why some elements were more reactive than others..

[Luigi84289]

@fongg2 Helium is a noble gas because it's stable. You only need 2 electrons in the first shell to fill it up. It won't react with anything normally. It's just 2 hydrogen atoms fused together. It's the product of Hydrogen fusion which fuels stars.

[Luigi84289]

@MrMcdagy Hydrogen generally bonds with other hydrogen atoms or oxygen. It pairs up naturally. You won't find just a single hydrogen atom in nature it always comes in pairs if it's free in a gaseous state.

[127miles]

may i point out that at 1:50 you say " these all have to 2 atoms in its outer most shell" just correcting :P

[ELECTRICxxxPENGUIN]

lol @ 11:40

[MapleOryDude]

what is desubshell?

[justaddsleep]

Aluminum is "more" of a metal, lol. Sounds like an e-peen contest.

[animafrea]

u help me understand the impossible!

[Azndvl614]

Your amazing

[rajo0105]

This is a little confusing. You've had to correct yourself a few times which would really throw off the students I work with! They are already struggling with these concepts and I need dsomething that would help them understand valence electrons and the properties of the groups!

[MrJas1991]

@rajo0105

Maybe you should teach them instead.

[guifercon]

Can you please, put a full-screen "crosshair"???

Or at least a colored one?

I lost several parts when you pointed and I missed the target

:-(

I'm a new fan of your videos!

Thanks for teaching us!

[01JH]

Your videos are great and I'd like to see them in order. Can you tell me how you've labeled them so I can view them in order? Thanks. Keep up the great work!

[chemsnippets]

These are wonderful videos with very few errors, and what errors are caught are often edited which is also a great way to show we are all humans. I see an error that is not corrected yet. Kr will have 4s24p6 and back fill in the 3d orbitals. Kr does not have a valence electron configuration of 3s23s6 as mentioned. Thanks for the great work; keep it up.

[TaughtTube]

electrons need 8 Electrons to stable......... and there are two elements which need 2 electrons to complete there duplet.......... H and He

[martaprentice]

My name is Mike from LA Although there busizz4me.info

[amy19741]

I never liked any of science subjects in my life. those subjects were born to be my enermy. I struggled with them for my whole life, the whole life. I even didn't care I get " 0" or not in those classes. right now, I can't wait to go to my biology class, can't wait, because I already know everything from your videos. oh, my god, thank you soooo much for the helps. God bless you, you are the best teacher.

[amy19741]

I haven't open my math or any of scients books since the day I went to school. those numbers just like monsters to me. I always got "0" in any of those subjects and I don't care. today, you totally change my life. I watch your video and can't let it go. I have confide to go to school and stay in the class. thannnnkkk youuuuuuuuuuuuuuuuuuuu. you are the best, God bless youuuuuuu./

[freeadplanet]

KHAN!!! The man. Thumbs up to say how awesome he is. Make him feel better to keep going with more!

[heartlessvietboy]

ALL WRONG !!!!!

[tay4tay4tay]

i need to use this fo r a science project its workin hehe

[areen1428]

amazing. thank you.

[techitow]

Isn't Gold the best conductor ?

[MyRealNameIs28]

@techitow No. It's silver really.

[njguitarnewbjk]

dude. my chem teachers name was dr. khan in high school are you him lol?

[aparnagadkari]

Hey thank u. This will help my children in learning periodic table

[girlicious102]

u rock!

[SuperBecksy]

This is a very clear video, but I have one problem.

So ionisation energy decreases as the number of electrons increase, and this is because there is more shielding and the attraction forces between the electrons and protons decreases. But the thing is that when the number of electrons increases, so does the proton number with it, so surely the increase in protons would sort out the attraction issue and make sure that the electrons are still strongly attached though????

[Tempestclaw]

These videos have helped me so much!

Just one question... do ALL of the transition metals have 2 valence electrons, or is it only the ones in the 3rd period? Just want to make sure of that...

[Underfaith]

Lol at Bara885's post

Also I just wanted to express my graditude for these wonderful vidoes!

[akx814]

..on a childs birthday lololololol

[hifhif123]

10:40 Is Kr 4s2-4p6, or 3s2-3p6

[LavaEaglez]

I now understand why there are such large deposits of metal and noble gases... they don't give a *&% about valence electrons since they have had their fill. Why certain elements explode with eachother and exactly why the hindenburg went up in flames besides "its flammable"

Thank you!

*Send to teacher

[azjeff1971]

Praise Elvis for these vids!!!!!!!!!!

[diamondwebs]

Thank you so much, Sal. Your videos are all amazing!

[Bara885]

I wonder why can't nobody find poeple like you in the class rooms. Man I cannot thanks enough. If you want to married my sister just let me know.

[Belxx]

@Bara885 HAHAHAHAHAHA you're legendary

[shivam01anand]

@Bara885 haha he's married

[7222Brit]

1:52 hmm i didnt know that all alkaline earth metals have two ATOMs in there outer most shell. Fail :) good videos

[tonocm]

lol :P

btw his videos rocks.

[7222Brit]

indeed it does

[gdf002]

@Vickiormindyb

My understanding is that when an atom has a full outer shell of 8 electrons it is at it's most stable. This is why the first 7 groups aspire to be like the 'noble gasses', as these gasses in group 8 have their outermost shell filled and are thus the most stable.

[POPITUNESPOPITUNES]

i am having so much trouble learning chemistry in class right now, thanks to this channel I'm starting to get it slowly.

[vickiormindyb]

When I was in 9th grade, we did an experiment with hydrogen and oxygen to create water.

When I put the hydrogen inside the tube, the whole beaker exploded and I got cuts all over my hand.

Other people were doing the same experiment and theirs weren't exploding. Other than the tiny explosion the teacher warned them about, theirs were fine. IDK where mine went wrong, but I needed medical attention.

After that experiment, I didn't like Introduction to Physical Science.

[LavaEaglez]

That is awesome! I would love to see random build ups of alkali metals xPP

[jessicalilac]

@vickiormindyb aw :(

[vickiormindyb]

And nobody knows why they want to have 8?

Another interesting fact is that it takes the heart 0.8 seconds to complete its beat in both upper and lower chambers.

[renaki]

your videos are great! they really helped me understand the periodic table. thanks for the vids.. keep uploading 'em!!! btw, can you make physics videos?? i'd really like to learn from that subject.

[vickiormindyb]

He already has a play list of Physics videos. I don't remember what it's called but I've seen some of them.

[daviddgiacoma]

great videos.

but when you use aluminium as the example for how electrons "back fill" in the D block is this incorrect?

[Ne] 3s2 3p1 for Al?

It doesn't have any electrons in the D shell?

or am I confused?

[khanacademy]

You are correct. Al doesn't have anything in the D sub-shell. Did I say it did? Let me add an annotation to fix that.

[vscoleman]

@khanacademy Minor meta-correction needed on the "Brain Malfunction" annotation at about 6:05. It says statement could have been made about Ga, Ln, or TI. The "Ln" really refers to Indium and should start with an "I" as in "I love good teachers".

[Spacehorse99]

@daviddgiacoma

Good for you Faggot Fuck your annoyng i hate people like you that think you know everything.

[ponit54]

lol explode at a child's birthday party that great way to end a lesson.