Question

are the isotopes that make up the air we breathe stable or unstable? a semistable b stable c unstable would calcium - 40 be stable or unstable? a semistable b stable c unstable

Explanation:

1. For the first question: The air we breathe is mostly composed of nitrogen-14, oxygen-16, argon-40, etc. These isotopes have balanced proton-neutron ratios and do not undergo radioactive decay, so they are stable.
2. For the second question: Calcium-40 has 20 protons and 20 neutrons, a 1:1 proton-neutron ratio which is stable for lighter elements. It is the most abundant and stable isotope of calcium, with no radioactive decay.

Answer:

1. B. stable
2. B. stable