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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: WhoTookMyUsername on January 15, 2011, 03:46:28 pm

Title: Physics
Post by: WhoTookMyUsername on January 15, 2011, 03:46:28 pm
HELP! Textbook is being annoying again. just starting unit 1 and  the question is:

Beryillium 9 is irradiated with neutrons. An alpha particle is released and it become a stable isotope. Identify the Nuclide.


So

Berrylium with 4 protons and 5 nuetrons + 1 neutron = alpha particle + ? - i think it's helium six but the book says lithium 6
Thanks!
Title: Re: Physics Noob
Post by: m@tty on January 15, 2011, 03:56:21 pm
An Alpha particle is 2 neutrons and 2 protons. So yeah, you're right it should be Helium 6.
Title: Re: Physics Noob
Post by: echenzi on January 15, 2011, 04:03:18 pm
He-6 is not stable, and will decompose to Li-6 (beta decay)..

I think thats the reasoning in your book.

But its horribly worded if it is the case.
Title: Re: Physics Noob
Post by: pi on January 15, 2011, 04:19:45 pm
He-6 is not stable, and will decompose to Li-6 (beta decay)..

I think thats the reasoning in your book.

But its horribly worded if it is the case.


+1, alpha decay and then beta-minus decay: Berrylium-9 + neutron --> Helium-6 (via beta-minus decay) --> Lithium-6

That must be it thanks alot  :)
2 more questions  :tickedoff:
Are there any rules or trends that indicate when a substance is unstable/radioactive?
Are there any rules or trends that indicate the relative length of the half life of a substance?

I don't there are any such rules/trends (or rules you need to know) about radionuclides... Probably the obvious one is atoms with large nuclei are generally more unstable than those with smaller nuclei (as a trend). But there are plenty of exceptions to that.
Title: Re: Physics Noob
Post by: schnappy on January 15, 2011, 05:29:36 pm
The ratio of protons to neutrons is a good indicator.

Also if you're dying.