Complete the exercises below. For each of the following metals, w...

Question

Complete the exercises below. For each of the following metals, write the electronic configuration of the atom and its 3+ ion: a. Fe. Draw the crystal-field energy-level diagram for the d orbitals of an octahedral complex, and show the placement of the d electrons for each 3+ ion, assuming a weak-field complex. How many unpaired electrons are there in each case?

Accepted Answer

Step 1: Determine the atomic number of iron (Fe), which is 26, and write its electronic configuration using the Aufbau principle: $$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^6$$ $$4s^2$$ $$3d^6.. $$Step 2: For the $$Fe^3+ $$ion, remove three electrons from the highest energy orbitals. Since 4s and 3d are close in energy, remove two electrons from 4s and one from 3d, resulting in the configuration: $$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^6$$ $$3d^5.. $$Step 3: Draw the crystal-field energy-level diagram for an octahedral complex. In an octahedral field, the five d orbitals split into two sets: t2g (lower energy, three orbitals) and eg (higher energy, two orbitals).. Step 4: Place the five d electrons of $$Fe^3+ in $$the t2g and eg orbitals according to Hund's rule, which states that electrons will fill an empty orbital before pairing up. In a weak-field complex, the electrons will remain unpaired as much as possible.. Step 5: Count the number of unpaired electrons in the d orbitals of $$Fe^3+. $$Since there are five d electrons and they are distributed among the t2g and eg orbitals with maximum unpairing, determine the number of unpaired electrons.

Concetti chiave

Electronic Configuration

Crystal Field Theory

Unpaired Electrons and Magnetism