<span>40 20Ca this is the appropriate symbol for an isotope of calcium-42 corresponding to the isotope notation AZX</span><span />
AXz
Explanation:
It is a chemical notation of nuclide
Here X is the symbol of the element
A is the mass number of element
A=n+p(sum of protons and neutrons)
Z is the atomic number.
For example, 12C6
Hers X is C, symbol of carbon
12 is the mass number and 6 is the atomic number of the carbon.
(20/23) times 100 is 87%
now the answer asks for percentage ERROR
100-87 =13
so answer is C
