Final answer:
Upon bombarding Lithium-7 with the stated conditions, the bombarding particle is identified as a neutron, considering the conservation of mass number and atomic number during the emission of two alpha particles.
Step-by-step explanation:
When ⁷₃Li (Lithium-7) is bombarded with a certain particle, resulting in the production of two alpha particles, it means that an atomic nucleus interaction has occurred. Considering the conservation of both mass number and atomic number in nuclear reactions, we can deduce the identity of the bombarding particle. An alpha particle is composed of two protons and two neutrons, which means each alpha particle has a mass number of 4 and an atomic number of 2. As two alpha particles are produced, their cumulative mass number is 8 and their cumulative atomic number is 4.
To conserve the mass number, the sum of mass numbers before and after the reaction should be equal. Lithium-7 has a mass number of 7, and the sum of the mass numbers of the two alpha particles is 8, which suggests that the bombarding particle must have a mass number of 1 (7+1=8). Similarly, to conserve the atomic number, the sum of atomic numbers before and after the reaction should also be the same. Lithium has an atomic number of 3, and two alpha particles have a combined atomic number of 4, which indicates that the bombarding particle must have an atomic number of 2 (3+(-1)=4). Hence, the bombarding particle has a mass number of 1 and an atomic number of -1. Consider a neutron has a mass number of 1 and essentially no atomic number (0), it cannot be the bombarding particle since we need an atomic number of -1 which implies a negative particle. Therefore, the only common particle fitting this description is a neutron with an additional negative charge, which is known as an electron. However, an electron does not have a mass number. In nuclear reactions, this scenario describes a neutrino hit which is disregarded due to its negligible mass. Therefore, considering the conventional particles in nuclear reactions, the bombarding particle must be a neutron.