Question

The electronic configuration of Neodymium (60) Nd is

• A. $[Xe] 4f^46s^2$
• B. $[Xe] 5f^1$
• C. $[Xe] 4f^26s^2$
• D. $[Xe] 5f^44d^1$

Answer 1

Answer: (A)

$[Xe] 4f^46s^2$

Answer 2

Solution: Neodymium (Nd) is an element with the atomic number 60, meaning it has 60 electrons. We need to find its correct electronic configuration.

Step 1: Electronic Configuration Strategy: The electronic configuration of elements is determined based on the Aufbau principle, Hund’s rule, and Pauli’s exclusion principle. The order of filling orbitals follows the increasing energy levels based on the (n + l) rule, where n is the principal quantum number and l is the azimuthal quantum number.

Step 2: Noble Gas Core Representation: The electronic configuration for Neodymium starts with the configuration of the nearest noble gas Xenon ([Xe]), which represents the filled electron shells up to atomic number 54:

$[Xe] = 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6$

Step 3: Filling the Remaining Electrons: After [Xe], the remaining 6 electrons for Neodymium fill the 4f and 6s orbitals. According to the Aufbau principle:

• The 4f orbitals have a lower energy level than the 5d and 6s orbitals, so they are filled first.
• The 4f subshell can hold up to 14 electrons.
  Therefore, the next electrons occupy the 4f orbitals:

$4f^4 6s^2$

Step 4: Final Configuration: Thus, the electronic configuration of Neodymium is:

$[Xe] 4f^4 6s^2$

Step 5: Verification: The options given are:

1. $[Xe] 4f^4 6s^2$
2. $[Xe] 5f^7 6s^2$
3. $[Xe] 4f^5 6s^2$
4. $[Xe] 4f^6 6s^2$

Thus, the correct answer is option 1.