When a nuclide absorbs a positron, several important changes occur to its properties. Let’s go through these changes step-by-step:
1. Understanding Positron Absorption:
- A positron is the antimatter counterpart of an electron, and it has a positive charge.
- During positron absorption, a proton in the nucleus of the atom is converted into a neutron. This means:
- The atomic number (number of protons) decreases by 1.
- The mass number (total number of protons and neutrons) remains unchanged.
2. Given Nuclide Characteristics:
- The starting nuclide is copper ([tex]${ }_{29}^{64} Cu$[/tex]).
- This indicates copper has an atomic number of 29 (29 protons) and a mass number of 64 (sum of protons and neutrons).
3. Effect of Positron Absorption:
- A proton converts into a neutron.
- So, the atomic number decreases by 1 (29 - 1 = 28) because we lose one proton.
- The mass number remains the same because the total number of nucleons (protons + neutrons) stays constant at 64.
4. Resulting Atom:
- With the new atomic number of 28, the element is no longer copper. Element 28 in the periodic table is nickel (Ni).
- The mass number remains 64.
Thus, the resulting atom is [tex]${ }_{28}^{64} Ni$[/tex]. Therefore, the correct choice is:
[tex]${ }_{28}^{64} Ni$[/tex]
