by assassinsdoc
 P: 7 Why c - 14 is radio active though n/p ratio is less than 1.5?
 Thanks P: 1,316 There is no "magic rule"; see the article on "nuclear drip line": http://en.wikipedia.org/wiki/Nuclear_drip_line
 P: 1,253 That is not a rule. Most radioactive elements do not have n/p > 1.5. That's a myth
P: 1,253

Do not confuse the statement "There are no stable nuclei with n/p > 1.5" with the statement "All unstable nuclei have n/p > 1.5". See the difference? The first one is true. The second one most definitely isn't.
Mentor
P: 10,834
 Quote by dauto Do not confuse the statement "There are no stable nuclei with n/p > 1.5" with the statement "All unstable nuclei have n/p > 1.5". See the difference? The first one is true. The second one most definitely isn't.
Lead-207 is (experimentally1) stable with 82 protons and 125 neutrons, 125/82=1.524.
There are a few other examples, see the linked list.
P: 1,253
 Quote by mfb Lead-207 is (experimentally1) stable with 82 protons and 125 neutrons, 125/82=1.524. There are a few other examples, see the linked list.
That's exactly my point. This rule is just an approximate rule of thumb...
 P: 7 thank you! I've studied in class about something called 'magic numbers' where nuclei having 2, 8, 20, 28, 50, 82 or 126 protons or neutrons or both (seperately) are exceptionally stable compared to their respective neighbouring nuclides. So, they too make an exception.
 Mentor P: 10,834 That's right.

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