Final answer:
The equation for the positron emission of Ga-68 is 0/-1 e → 68/31 Ga. In this type of decay, a proton is converted into a neutron, and a positron is ejected from the nucleus, resulting in a decrease in the atomic number by 1.
Step-by-step explanation:
The equation for the positron emission of Ga-68 is option D) 0/-1 e → 68/31 Ga.
In positron emission, a proton in the nucleus is converted into a neutron, and a positron (a positively charged electron) is ejected from the nucleus. This results in a decrease in the atomic number by 1 and no change in the mass number. In the case of Ga-68, which has an atomic number of 31, the emission of a positron results in the formation of Ge-68, which has an atomic number of 32.