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Representative elements, Why this name?


Arnav
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Why are representative called so? If I google it, the majority of people state its because their outermost energy levels are not completely filled. But isn't it absurd to name them "representative elements" then? what is the logical reason behind it?

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I believe you misinterpreted my question, in which I asked about representative elements,(entire s-block and p-block except noble gases) while you, I believe, are talking about typical elements, the elements of period 3.

Screenshot_2021_0725_235520.jpg

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41 minutes ago, Arnav said:

I believe you misinterpreted my question, in which I asked about representative elements,(entire s-block and p-block except noble gases) while you, I believe, are talking about typical elements, the elements of period 3.

Screenshot_2021_0725_235520.jpg

Yes, it’s another term for the main group (but also includes the noble gases) and has the property I described. They are also the most abundant of the elements

https://en.wikipedia.org/wiki/Main-group_element

 

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2 hours ago, Arnav said:

Why are representative called so? If I google it, the majority of people state its because their outermost energy levels are not completely filled. But isn't it absurd to name them "representative elements" then? what is the logical reason behind it?

The "representative element" seems to be barely used, and I would agree with you that it seems to be a fairly useless concept. Representative of what? The division of groups into A and B has long since been given up. It makes far more sense to speak of s, p, d and f blocks of the Periodic Table.

I don't know how representative (haha) my personal experience is but I, at least, went through a 4 year chemistry degree course back in the 1970s without the term "representative element" being used once, so far as I can recall. The term does not appear anywhere in my 1972 edition of Cotton & Wilkinson.  

I'd actually be rather interested to know who is suggesting to you that this terminology is relevant, and why.

 

Edited by exchemist
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3 hours ago, Arnav said:

Why are representative called so? If I google it, the majority of people state its because their outermost energy levels are not completely filled. But isn't it absurd to name them "representative elements" then? what is the logical reason behind it?

 

32 minutes ago, exchemist said:

The "representative element" seems to be barely used, and I would agree with you that it seems to be a fairly useless concept. Representative of what? The division of groups into A and B has long since been given up. It makes far more sense to speak of s, p, d and f blocks of the Periodic Table.

 

The representative elements are those identified in Mendelev's original tables 169 to 1871 as fitting into the 'a' groups, in each column.

The orginal tables did not look anything like our modern version so here is a modernised version of Mendelev

showing the classification scheme.

This was to use Roman numerals to show originally six columns, later increase to eight and then nine.

Each column was further divided into two sub columns, labelled a and b.

I have ringed the a in my attachment.

Elements in the a column were called 'representative elements' (my translation has 'the typical elements').

Mendelev classified by chemical compounds and reactions.

It was not until 1913 that the modern atomic number listing was established by Mosely's square root law.

mendelev1.jpg.80d9d22bcf2ea0c89c80c72c1013666a.jpg

 

 

As exchemist says, the classification is obsolete today.

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37 minutes ago, Arnav said:

okay thanks guys. I dont know why the books in our education system still use the old terminology like representative elements😬

The table I quoted came from the high school textbook I used in the 1960s

Comparative Inorganic Chemistry.

B J Moody

I regard is as still the best book of its type and the history I gave was precis of chapters 2 and 3, which take the reader through from Dalton to Quantum Chemistry.

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On 7/26/2021 at 10:03 PM, studiot said:

The table I quoted came from the high school textbook I used in the 1960s

Comparative Inorganic Chemistry.

B J Moody

I regard is as still the best book of its type and the history I gave was precis of chapters 2 and 3, which take the reader through from Dalton to Quantum Chemistry.

Oh nice 🙂

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On 7/26/2021 at 4:46 PM, Arnav said:

okay thanks guys. I dont know why the books in our education system still use the old terminology like representative elements😬

Yes, it's curious. Out of interest, whose education system are you talking about - if you don't mind saying?

I can see the value of mentioning it in the context of the history of the Periodic Table, if you are studying that, but not for the practice of modern chemistry. 

 

Edited by exchemist
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Many indian books have that term...not under the topic of historical development of periodic table, rather under the topic modern periodic table and the broad classification of elements in it.

They state that s,p blocks are called representative elements and don't give any reason 

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