Final answer:
In Fe₂, each iron atom has 6 d electrons.
Step-by-step explanation:
Iron has an atomic number of 26 and an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶. In Fe₂, we have two iron atoms, so we need to determine the number of d electrons present in each iron atom. The d electrons are found in the 3d orbital. From the electronic configuration, we can see that there are 6 d electrons for each iron atom in Fe₂.
The question asks how many d electrons are present in Fe₂, which refers to two iron atoms combined, each having lost electrons typical in an iron(II) state. The atomic number of iron is 26, indicating 26 protons and, in a neutral state, 26 electrons. Iron's electronic configuration is [Ar] 4s² 3d⁶. When iron forms a Fe²⁺ ion, it loses two electrons which are generally taken from the 4s orbital, leading to the configuration [Ar] 3d⁶. This means that each Fe²⁺ ion has six d electrons, so for Fe₂ (two iron ions), there would be a total of 12 d electrons.