Write the electron configurations for both Mo and Mo4+ Cele
The Correct Answer and Explanation is:
The electron configuration of an element gives the distribution of its electrons in atomic orbitals, following the principles of the Aufbau principle, Pauli exclusion principle, and Hund’s rule. Let’s go through the electron configuration of both the neutral molybdenum atom (Mo) and its Mo4+ ion.
Molybdenum (Mo) Electron Configuration:
Molybdenum has an atomic number of 42, which means it has 42 electrons. The electron configuration of Mo follows this sequence:
Mo: [Kr] 4d^5 5s^1
Here’s how we break it down:
- [Kr] represents the electron configuration of krypton, which accounts for the first 36 electrons.
- After krypton, molybdenum adds 6 more electrons, filling the 4d and 5s orbitals.
- The 5s orbital is filled first, and then the 4d orbital. However, molybdenum has an unusual electron configuration where one electron from the 5s orbital moves to the 4d orbital to achieve a more stable configuration. This results in 4d^5 5s^1 instead of the expected 4d^4 5s^2.
Molybdenum (Mo4+) Electron Configuration:
The Mo4+ ion is formed when molybdenum loses 4 electrons. Since Mo’s electron configuration is [Kr] 4d^5 5s^1, the first electrons to be removed are from the 5s and 4d orbitals.
When Mo loses 4 electrons:
- Two electrons are removed from the 5s orbital (since it is higher in energy than the 4d orbital).
- Two electrons are removed from the 4d orbital.
So, the electron configuration of Mo4+ is:
Mo4+: [Kr] 4d^2
This indicates that, after losing 4 electrons, the Mo4+ ion has the same electron configuration as the element zirconium (Zr), which also has 40 electrons. The 4d subshell now holds 2 electrons.
Explanation:
The reason molybdenum adopts this configuration is due to the relative stability of having half-filled (4d^5) and full (5s^2) subshells. When it forms the Mo4+ ion, it loses the electrons in a way that minimizes repulsion and maximizes stability. The 4d^5 configuration (in Mo) is relatively stable because it leads to a half-filled d-subshell, which is energetically favorable. However, after ionization to Mo4+, the remaining 2 electrons occupy the 4d orbital in a stable configuration with lower energy.
