Write the ground-state electron configuration for a neutral atom of each element: vanadium x 6? Chromium
The Correct Answer and Explanation is:
Here are the correct ground-state electron configurations for each element:
✅ Vanadium (V, Atomic Number 23)
Electron Configuration:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³
Or using noble gas shorthand:
[Ar] 4s² 3d³
✅ Chromium (Cr, Atomic Number 24)
Electron Configuration:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
Or using noble gas shorthand:
[Ar] 4s¹ 3d⁵
💡 Explanation (Approx. 300 words):
Electron configurations describe how electrons are distributed in an atom’s orbitals. The goal is to follow the Aufbau principle (filling lower-energy orbitals first), Pauli exclusion principle, and Hund’s rule for the most stable arrangement.
For vanadium (V), which has 23 electrons, the configuration proceeds normally by filling up orbitals in order of increasing energy levels: 1s → 2s → 2p → 3s → 3p → 4s → 3d. So, the electrons are arranged as:
- 2 in 1s
- 2 in 2s
- 6 in 2p
- 2 in 3s
- 6 in 3p
- 2 in 4s
- 3 in 3d
Thus, V is written as [Ar] 4s² 3d³.
Chromium (Cr), with 24 electrons, is an exception to the expected pattern. One might expect [Ar] 4s² 3d⁴, but this is not the most stable configuration. Instead, chromium “borrows” one electron from the 4s orbital and places it in the 3d orbital, forming [Ar] 4s¹ 3d⁵.
Why this happens: Half-filled (like d⁵) and fully-filled (like d¹⁰) subshells offer extra stability due to electron symmetry and exchange energy. So, 4s¹ 3d⁵ is energetically more favorable than 4s² 3d⁴.
These configurations help in predicting chemical behavior, bonding, magnetic properties, and placement in the periodic table.
