Chapter 18 Numerical Problems Examples

Example 18.1: Find the number of protons and neutrons in the nuclide defined by .  ¹³X₆ 
Solution: From the symbol, we have Atomic number Z = number of protons =6

Atomic mass A = number of protons + number of neutrons = 13
But number of protons are 6, so number of neutrons will be 7.
So the element is an isotope of carbon-6, and is written as
¹³X₆

NUCLEAR TRANSMUTATIONS

Example 18.4: The C-14: C-12 ratio in a fossil bone is found to be 1/4^th that of the ratio in the bone of a living animal. The half- life of 
C-14 is 5730 years what is the approximate age of the fossil?
Solution: Since the ratio has been reduced by factor of 4 therefore, two half-lives have passed.
Therefore age of the fossil is given by: 2 x 5730 = 11460 years

 

Half Lives of Selected Isotopes

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