h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Atoms and Isotopes: Pre-university Level - A87762171
Author: mikeyc0312 - U612358

Here is the rescued version of nicki's article on atoms and isotopes I haven't changed much, just added a section on Molar mass.

It's great to see this back - and so quickly too! Thanks for taking this onboard

For reference - the first version can be seen here: A87722012 Atoms and isotopes - A level Standard

The first version's Peer Review thread is here: F22118310?thread=8285358

Have you read through the previous Peer Review thread and taken the previous suggestions etc into account? I remember there were suggestions such as links to related articles etc.

<BB<

Honestly, I don't see this article having a future with its current title. I don't think that any hootoo-size article, presently construed, is going to manage this title. I would recommend something more like 'A Brief Primer On The Chemical Element'.

I am very much in favour of Guide Entries that help the physics and chemistry handicapped. I say this in all sincerity, as one who has PTSD from university. The mere mention of 'the dipole nature of water' will send me into shell-shock. So if you're explaining this stuff, bless you, you're a benefactor to the human race.

Here are some queries of mine, based on reading this as if I didn't know anything at all - which isn't hard, believe me. (Just ask Profs Kaufmann, Levine, Cohen, and any number of terrified teaching assistants.)

'The excepted model' - unless I'm *really* confused (possible), isn't this 'accepted'?

'This is known as the atomic number and given the symbol z.' - I have no idea what this means. What is given the symbol z? Carbon?

'Note: this is NOT the same for ions.' - What's an ion? Please explain here.

'The atom is too small to weigh...' - Why is the atom too small to weigh? Are there no instruments for this? No tiny scales?

'The number of atoms in a mole of a substance is known as Avogadro’s Number.' - How about a footnote on who Avogadro was, and why he's entitled to his own number?

'Measuring relative atomic mass' - As this is potentially an exciting process (yeah, I know it's not, I've stood around watching it, but let's pretend), how about an introductory statement as to why you might want to measure this, and how interesting the proceses will be? Opportunity for humour here.)

'The problem with relative molecular mass is for giant ionic structures such as SiO2...' This is cool, but could you tell us what SiO2 is when it's at home? Is it good for something awesome? Any reason why you picked silicon dioxide, anyway?

How about a summary at the end of this, telling us lab rats what we're supposed to have learned?

A link or two for further reading would be much appreciated. By now, there *has* to be an online version of 'Chemistry for Dummiers'.

Mikey

Thanks so much for rescuing this Entry. We really appreciate Flea Market rescues.

I've got a feeling that the title was altered previously. I'll give it some thought and come up with some alternatives for you to think about. The title has to be something that someone using a search engine will recognise as being 'what they are looking for' so the suggestion by Julez didn't give me that sense of immediacy that the words 'Atoms and Isotopes' do.

You might consider having a title - simple and direct explanation of the focus of this Entry - shorter is better to be honest. If you can crystallise the whole of the Entry into less than six or so words you're onto a winner.

A sub title - ie a phrase at the very top of the Entry itself is also a means to encouraging readers that they have arrived at the very article that is going to help them. I know that nicki wrote a series of Entries to help students with their A-levels ( UK Centric) which is why the pre-university part of the title crept in.

Anyway, I am encouraged to see this here! Well done so far.



Lanzababy

Hi Dmitri.
I have corrected the mistake. It should indeed have read 'accepted'. z is the symbol for the atomic number of any atom. An ion is an atom which has lost or gained electrons, imparting it with charge. Metal and non-metal atoms use this to bond, making ionic compounds. An example is Sodium Chloride, NaCl, also known as table salt. As to atoms being too small to measure, it is true that atoms have insufficient mass to be measured in the way we normally do. The article does show how the mass of atoms and molecules is determined. Silicon Dioxide is sand. It was, I assume, chosen because it is quite a well known example of a giant lattice molecule.
I hope this has helped answer some of youer questions.

Hi, Mikey. Thanks for the changes.

What I was suggesting in my list was not that you answer the questions here, but that you answer them in the entry.

I think saying, 'This is NOT the same for ions', without explaining it, is confusing to the reader.

The same with SiO2 - I think there should be an explanation in-text of what it is, why it's chosen, etc.

I didn't have time to read through this again and I can't remember what I said in the original PR thread, but I'll try to get back to this.

This entry seems to have fallen by the wayside somewhat, but I have added the information I relayed to Dmitri and also a link to the entry on the periodic table. Any further feedback would be appreciated.

Oh, that's really MUCH better, Mikey. Thanks!

This isn't something you need to do, but I'd like to leave a note here for a future sub-editor: this entry really needs more commas. I can tell, because I have to read a lot of sentences three times before I get the meaning.

This isn't a subject I know a great deal about, but I've had a look through the previous Peer Review thread and it looks like the suggestions still outstanding from that one are:

Links to articles on:
Carbon A6359060
Atoms and Atomic Structure A6672963
Radioactivity A661727
Atomic Mass and Atomic Mass Unit A9914466

(Incidentally, Tav, you didn't comment in the previous PR thread)

<BB<

Thanks for digging this out of the backlog BB. Much appreciated.

I'll give this some deep thought.

but which Entry was it then to which I commented? Was there another one like that?

Sorry, I saw it was this Entry I commented to: A87721743

Great idea.

To start with, I have a pet peeve about unnecessarily misrepresenting science or history under the guise of "introductory" anything. therefore, my bias thus expressed, may I help by adding the following:

"The atom is the smallest part of an element that can exist on its own." seems technically incorrect. The idea is "...without changing the properties of that element."

AE

Perhaps you need to define a chemical element.

"...modern microscopes but this is a recent development."

"modern" and "recent" are relative terms that will date this entry in short order--given how fast science is changing.

"as of 2012,..." might help, but something like just dating the first electron microscope image of atomic structure would be better.

I am here only making a very general suggestion, trying not to be too specific.

"The accepted model is composed of 3 sub atomic particles "

Could be:
"Most models are composed of three [not 3] major subatomic particles..."

"The mass of an electron is negligible and is therefore ignored."

could be:
"The mass of an electron is negligible and is generally ignored."

But in difference to other comments, even the "negligible" mass of the electron has been measured.

“The protons and neutrons are contained in the nucleus but the electrons orbit the nucleus in shells or orbitals.”

Could be:
“Neils Bohr introduced an important model of atomic structure in 1913. In that model the protons and neutrons are in the center, called the nucleus, and the electrons orbit the nucleus in shells or orbitals.”