Exceptional configurations of Cr and CuCr और Cu के अपवाद विन्यासExceptional configurations of Cr and Cu

Class 12 Chemistry · Chapter 4 · interactive diagram

Parts and what they mean

• Cr expected: 3d⁴ 4s² (Cr अपेक्षित: 3d⁴ 4s²) — What the simple filling order would give. Not the real ground state.
• Cr actual: [Ar] 3d⁵ 4s¹ (Cr वास्तविक: [Ar] 3d⁵ 4s¹) — One 4s electron moves into 3d: five singly filled d orbitals with parallel spins (6 unpaired electrons in all).
• Cu expected: 3d⁹ 4s² (Cu अपेक्षित: 3d⁹ 4s²) — Simple filling order — not the real ground state.
• Cu actual: [Ar] 3d¹⁰ 4s¹ (Cu वास्तविक: [Ar] 3d¹⁰ 4s¹) — A completely filled 3d¹⁰ set is more stable, so one 4s electron moves into 3d.
• Half-filled d⁵ (अर्धपूर्ण d⁵) — Half-filled sets have extra stability (maximum exchange energy).
• Completely filled d¹⁰ (पूर्ण भरा d¹⁰) — Completely filled sets are also extra stable.
• Small 3d–4s energy gap (3d–4s में कम ऊर्जा अंतर) — Because (n–1)d and ns are so close in energy, a small stability gain is enough to shift an electron.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake