The condensed electron configuration for ²⁴Cr is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵ [Ar] 4s² 3d⁴ [Ar] 4s¹ 3d⁵ Show answer 📝 Detailed explanation Chromium is an exception to the expected filling order. One electron is promoted from the 4s orbital to the 3d orbital, giving the more stable configuration [Ar] 4s¹ 3d⁵.