Re: Question about Helium vs Helium-4

Jim wrote:
Hi Borek
On Mon, 26 Jun 2006 17:54:15 +0200, Borek
<m.borkowski@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Mon, 26 Jun 2006 16:11:34 +0200, Jim <Jim@xxxxxxxxxxxxxxxx> wrote:

I came across something that has me puzzled. My understanding is that
a helium atom has 2 protons and 2 neutrons. I also understand that an
isotope for an element is that element with the same number of protons
but a different number of neutrons.

I came across a definition of helium-4. The description says that it
is a light isotope of helium and that it has 2 protons and 2 neutrons.

My question is how can it be an isotope, let alone a "light" isotope,
if its nucleus contains the same number of protons and neutrons as
regular helium.

Check definition of isotope - you are _almost_ right. All atoms containing
same number of protons are isotopes, regardless of number of neutrons.

Best,
Borek


Okay. So how can you have an atom be an isotope when it contains the
same number of protons and neutrons as the base element?

Helium-3 is an isotope of helium because it contains 1 instead of 2
neutrons.

Helium-10 is an isotope because it contains 8 neutrons instead of 2
neutrons.

So how can helium-4 be an isotope of helium when it's number of
neutrons is the same as helium?


Here is the helium nucleus: PPNN

Here is the helium-3 nucleus: PPN

Here is the helium-10 nucleus: PPNNNNNNNN

Here is the helium-4 nucleus: PPNN

Looks to me like there is no difference between the helium atom and an
atom of helium-4. My question is why?



Read post #4, by Craig VERY carefully. It has answered both your first
and last post. Maybe I can rephrase it for you. You asked:

So how can helium-4 be an isotope of helium when it's number of
neutrons is the same as helium?

Your familiar "helium" and helium-4 are the same substance. When you
fill your balloon with "helium" you are using helium-4.

Helium-4 is but one isotope of many known variations of helium. You
are incorrectly setting a useless baseline simply because helium-4 is
the predominant form here on Earth. Helium-4 is no more "helium" than
helium-3 or helium-10 are. Therefore, they are ALL isotopes OF EACH
OTHER.

If this hasn't helped, then just take the definition you found as 100%
correct and forget these somantics since it seems you have a proper
understanding (going off your PPNN diagrams) of what's going on with
the differences in isotopes. You'll probably reread one of these posts
and smack yourself on the forehead, saying "why didn't I get that
before?". It's happened to all of us (AKA "brain fart").

.

Relevant Pages

  • Re: Hot Big Bang
    ... Energy is released in an explosion. ... the Big Bang would create protons and neutrons. ... two are helium. ...
    (talk.origins)
  • Question about Helium vs Helium-4
    ... a helium atom has 2 protons and 2 neutrons. ... is a light isotope of helium and that it has 2 protons and 2 neutrons. ...
    (sci.chem)
  • Re: Question about Helium vs Helium-4
    ... a helium atom has 2 protons and 2 neutrons. ... is a light isotope of helium and that it has 2 protons and 2 neutrons. ...
    (sci.chem)
  • Re: Question about Helium vs Helium-4
    ... a helium atom has 2 protons and 2 neutrons. ... is a light isotope of helium and that it has 2 protons and 2 neutrons. ...
    (sci.chem)
  • Re: Question about Helium vs Helium-4
    ... My question is how can it be an isotope, let alone a "light" isotope, ... if its nucleus contains the same number of protons and neutrons as ... Helium has isotopes ranging from 3 to 10. ... Helium-10 is an isotope because it contains 8 neutrons ...
    (sci.chem)
Quantcast