Periodic Classification of Elements

Periodic Classification of Elements: Let's explore Dobereiner's Law of Triads and Newland's Law of Octaves in this video! In the history of the Periodic Table, these were the initial attempts to group elements. We also discuss why do we need to classify elements and the need of a Periodic Table in Chemistry.

Try the Top 3 Questions at the end of video and write your answers and doubts in the comments below!

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[lpbugvf]

Q1) Dᴏʙᴇʀᴇɪɴᴇʀ ɪᴅᴇɴᴛɪғɪᴇᴅ 3 ᴛʀɪᴀᴅs
✓ Lɪ, Na, K
✓Ca, Sr, Ba
✓Cl, Br, I

Q2 ) 40+ x/ 2= 88
x = 136

Q3) • it was valid for lighter elements i.e upto calcium (Ca)

• He placed two elements in a single group (slot)eg: (Co, Ni) ; also the properties of Co and Ni were not matching in which he had placed with cl, br, I etc

Thnku sir for giving us hw 💯

[Neeraj-yzhp]

1.Three triads
2.136
3.(i)The law succed only upto calcium element not further it
(ii)There were no arrangement to add new discovered elements as Newland think that only 54 elements can be possible.


Note: -2 Que explained, as if they are triads

b=a+c/2
88 =40+c/2
88×2=40 + c
176 = 40 + c
176 - 40 =c

136=c...


That 's all.

[PramodKumar-krvd]

One of the best teacher I never seen sir. Thank u sir for providing some classes freely.
Q 1. 3
Q 2. 136
Q 3. It is suitable upto calcium
And two elements in one box

[thestrangeone]

Hi sir, you are the best teacher,
And the answers for the homework questions are :
I) Dobereiner was only able to identify 3 triads .
ii) we know that (element A+element C)/2 = elements B
(40+C )/2=88
40+C=88*2
40+C=176
C=176-40
C=136
Therefore answer is 136
iii) 2 issues in Newlands octaves were :
a)it was only applicable till element calcium .
b)newland assumed that only 56 element will exist and no another element will be found in future, but later when new element were discovered Newlands law of octaves became completely irrelevant
BUT HIS LAW WORKED VERY WELL IN ELEMENTS CONTAINING LIGHT ATOMIC
SIR
THANKS
A
LOT
FOR
AN
EXTODINARY
SESSION

[a.pal_yt]

My answer!
Q1. Three traids, (average of atomic mass of 1st and 3rd element is approximately equal to the atomic mass of 2 ND element . )
Q2. We know that, average of atomic mass of 1st and 3rd element is approximately equal to the atomic mass of 2 ND element in order, let us assume C to be x, thus, (A+x)/2=88, (40+x)/2=88 or, 40+x=176, or, x=136u
Atomic mass of c is 136u
Q3. The two issues were - the table could be valid for the lighter elements till calcium (Ca) .
There were only 56 elements discovered till that time (1866) but after the exploration of new elements caused issues and demerits of NewLands table.






Edit : Thanks a lot! You are a true teacher 🙏🙏 You helped me memorising full book of science in a month.

[Sajid-skut]

Sir i am from kendriya vidyalaya. My science teacher sent this link to me for a good explanation. Thanks alot for your explanation.

[abhzt]

You are the best teacher on YouTube i have found till now!

[haripriyakolli]

1) 3
2)A+C/2=B
40+C/2=88
40+C=88×2
40+C=176
C=176-40
C=136
3)i. He kept two elements in same slot
ii.his law was only applicable for 56th element that is calcium
ii.

[ashwinmanoj]

I was trying to help my son with the chapter. Stumbled on this video accidentally. Found it very helpful. Most striking thing is that it is explained in a very simple manner. Excellent work Sorry, don't know your name.

[gubbalasrinivas]

1) 3 triads
2) A+C/2=B
40+C/2=88
40+C=88×2
C=176-40=136
3)He plced two elements in the same slot
The Newlands law of octaves is only valid till calcium

[samsteven]

Sir thank you so much
I was crying for my tomorrow's chemistry
My senior suggested this YouTube
Thanks a lot
I'll share this channel in my class sir....
Once again thanks for infinity

[shailendraduggal]

Q1. 3
Q2. (40+x)/2 = 88
x = 136
Q2. a)The classification worked only on the first 20 elements.
b)Newland adjusted two elements cobalt and nickel in the same slot and these were placed in the same column as fluorine, chlorine and bromine which have very different properties from co and ni.

[BirdGuy]

Q1. 3
Q2. Approximately 136, because:
(A + C)/2 = B
Hence (40 + C) = 88 * 2
40 + C = 176
C = 176 - 40,
Hence *C = 136*
Q3.
i. It only was applicable till calcium.
ii. It put two elements in one box.
iii. It only took into account the 56 elements that were then discovered, and when more were discovered, many elements could not be fit into the table.

[lizzy]

Ans 1. Dobereiner identified 3 triads
Ans 2. 136
Ans 3. (i) It was applicable only till calcium
(ii)cobalt and nickel were placed with elements like hydrogen, fluorine, chlorine, bromine, etc whose chemical properties are very different from that of cobalt and nickel

[bandaruapparao]

A1-3 triads
A2-136
A3-in the time of newland there were only 53 elements, and when new elements are discovered the properties of those new elements didn't Sir the concept is crystal clear to me Thank you sir.

[deshpande]

Now it is exams time so I didn't understand the concept related to this..And I searched in youtube and found ur video...
It's really easy for me now..Thank u

[ranakaushik]

Answers:
1)Dobereiner identified 3 triads
2)Let us assume C=x
Given A=40, B=88
According to question,
A+C/2=B
=>40+x/2=88
=>40+x=2x88
=>40+x=176
=>x=176-40
=>x=136
Thus, the atomic mass of the element C is 136
For checking,
A+C/2=B
=>40+136/2=88
=>176/2=88
=>88=88
Thus, L.H.S=R.H.S.

3)The 2 issues are:
i)Newland thought that there were only 56 elements in nature.
ii)The Law of Octaves was only applicable up to Calcium(Ca).
I hope, that I have given the right answers..
I am from West Bengal..

[muthulakshmi]

Q.1 dobereiner identified only 3 triads
0.2 atomic mass of 3rd element is 64
Q.3 1 issue: The table was only valid till calcium.
2 issue was: he assumed that there are only 56 elements there in nature
Lastly i would really thank you for explaining this topics in a simple way i really loved ur explanation
I have test today i was really confuses of this topics..But now i am crystal clear..
Thanks for your big support 🤩

[Royhana-iv]

Sir ....frm u...am really become a good speaker....in English much better than before.... because u teach as excellent as u

[gedamuteshome]

it is intersting vidio and thank you for your explanation
Top 3 question concerning about periodic table
Q1 Three B/c law of triads means 3 elements
Q2 according to Doberner law the atomic mass of the middle element is the avarage of the frist and the therd incas
atomic mass ofA+atomic mass of C divided by two gives B
massB=massA+massC/2
88=40+mass C/2
88×2=40+massc
Mass of C=88×2-40
136g/mole
Q3 1)He pleaced two elements in one place
2) the law applicable for only light element