View previous topic | View next topic

Isotopes, isomers etc

Page 1 of 1

Leo T
825999.  Wed Jun 22, 2011 5:52 pm Reply with quote

Some atomic and molecular trivia:

Isotopes are atoms that have the same number of protons, and thus are classified as the same element. For example, deuterium and tritium are both isotopes of hydrogen, having one and two neutrons respectively. Normal hydrogen nuclei have no neutrons.

Isomers, in nuclear physics, are atoms that have the same number of protons and neutrons, but where some of the protons or neutrons are excited to a higher energy state,much like electrons in an atom can be. Isomers with excited nucleons are formed in nuclear reactions and usually decay quickly by shooting off a energetic photon, or occasionally by transferring the extra energy to one of the atom's electrons which will fly off at high speed, ionising the atom.

Isotones are atoms that have the same number of neutrons but different numbers of protons, for example deuterium (one neutron, one proton) and helium-3 (one neutron, two protons).

Isobars are atoms that have the same total number of nucleons, for example helium-3 (2 protons + 1 neutron = 3 nucleons) and tritium (1 proton + 2 neutrons = 3 nucleons). The total number of nucleons in an atom is called the mass number because it is often roughly proportional to the atom's mass.

Isomers, in chemistry and molecular physics, are molecules that contain the same atoms but in different structures.

Isotopologues are molecules that contain the same elements in the same structure, but where some of the atoms are different isotopes. An example of two isotopologues is ordinary water (H2O) and heavy water (HDO, where the D is deuterium rather than ordinary hydrogen).

Isotopomers are molecules that contain the same elements in the same structure with the same isotopes, but where isotopes of the same element occur in different places in the structure.

 
Jenny
826223.  Thu Jun 23, 2011 3:08 pm Reply with quote

Welcome LeoT - what a shame we've just recorded the I series :-) Better start looking up chemistry QI stuff beginning with J!

 
Bondee
826226.  Thu Jun 23, 2011 3:12 pm Reply with quote

Jenny wrote:
Better start looking up chemistry QI stuff beginning with J!


Does this mean that it's been commissioned?!?

Errr... sorry. How do, Leo.

 
Jenny
826237.  Thu Jun 23, 2011 3:42 pm Reply with quote

Well we live in hope, Bondee... but I haven't heard one way or the other yet. Probably won't know until the autumn.

 
suze
826254.  Thu Jun 23, 2011 4:20 pm Reply with quote

Jenny wrote:
chemistry QI stuff beginning with J!


There isn't an element beginning with J.

To make it worse, I just checked out an online dictionary of chemistry, and there were only two entries for J. One of those was "joule", which is more physics than chemistry. The other was "Jones reductor", which turns out to be a tube full of zinc and seems to be little used outside the university laboratory. So that show might be quite a difficult one to write!

Perhaps we'll do have to do "J for Jenny" instead ...

 
Jenny
826258.  Thu Jun 23, 2011 4:26 pm Reply with quote

Well I am Quite Interesting, but I doubt whether a question that would show my full Interestingness could be formulated.

 
mckeonj
826276.  Thu Jun 23, 2011 5:29 pm Reply with quote

What about J-rays, then?
Captain J could not do what he does without his J-ray invisioniser.

 
exnihilo
826631.  Sat Jun 25, 2011 7:54 am Reply with quote

More biochemistry, but how about Jacobson's Organ?

 
soup
826718.  Sat Jun 25, 2011 1:55 pm Reply with quote

exnihilo wrote:
More biochemistry, but how about Jacobson's Organ?


Didn't realise it was so widespread, knew snakes had one, but didn't know most people have one too.

 
Moosh
827306.  Mon Jun 27, 2011 3:41 pm Reply with quote

I'm not a chemist but I know some words that begin with iso...

An isometry is a map between spaces that preserves the distance (or metric). So if f is a map between two spaces, then f is an isometry if the distance between two points a and b in the first space is the same as the distance between f(a) and f(b).

An isomorphism is a map between mathematical structures that is invertible and such that both the map and its inverse preserve the structure. What this actually means depends on what structures are being discussed but the point is that if there is an isomorphism between two structures (i.e. they are isomorphic to each other) then for all practical purposes they're the same structure.

 

Page 1 of 1

All times are GMT - 5 Hours


Display posts from previous:   

Search Search Forums

Powered by phpBB © 2001, 2002 phpBB Group