Answer:
Sn and B
Explanation:
An element is stable when the number of electrons is at their expected, which can be determined by looking at atomic mass on the periodic table. For this question, it is also important to note isotope notation, in which the top number is the atomic mass of that particular isotope, and the bottom number is the atomic number corresponding with that element. We can figure out if an element is stable by comparing its given isotope to the real atomic mass given on the periodic table:
- C is not stable because this isotope has a mass of 15, which is far from the expected atomic mass of 12 typically associated with C
- Sn is stable because the given 119 isotope is close to the atomic mass of 118, which is the atomic mass of Sn
- Al is not stable because its isotope is 29, which is not very close to the stable and expected mass of 27 (this may potentially be close enough, but typically it is not considered to be so unless it is within 1 unit of atomic mass from the mass given by the periodic table)
- B is stable because the isotope has an atomic mass of 10, which is very close to the atomic mass of B given by the periodic table of 11
Therefore, Sn and B are expected to be particularly stable.
