Use the periodic table and your knowledge of isotopes to complete these statements.

Question

When polonium-210 emits an alpha particle, the child isotope has an atomic mass of ...
.
I-131 undergoes beta-minus decay. The chemical symbol for the new element is ?
.
Fluorine-18 undergoes beta-plus decay. The child isotope has an atomic mass of ?

Answer 1

1. When polonium-210 emits an alpha particle, the child isotope has an atomic mass of 206. (Polonium-210 has an atomic number of 84. When it emits an alpha particle, it loses 2 protons and 2 neutrons, resulting in an isotope with an atomic mass of \(210 - 4 = 206\) and an atomic number of \(84 - 2 = 82\), which corresponds to lead, or Pb.)

2. I-131 undergoes beta-minus decay. The chemical symbol for the new element is Xe. (Iodine-131 has an atomic number of 53. Beta-minus decay involves the conversion of a neutron to a proton, which increases the atomic number by 1, resulting in an atomic number of 54, corresponding to xenon.)

3. Fluorine-18 undergoes beta-plus decay. The child isotope has an atomic mass of 18. (Fluorine-18 has an atomic number of 9. Beta-plus decay involves the conversion of a proton into a neutron, which decreases the atomic number by 1, resulting in an atomic number of 8, corresponding to oxygen, but the atomic mass remains 18 since it doesn't change in this process.)