Fe²⁺: [Ar]3d⁶ — has 6 d-electrons. Mg: [Ne]3s² — has 2 s-electrons? No, all s-electrons of Mg: 1s²2s²3s² = 6 s-electrons ✓. Cl p-electrons: 2p⁶ + 3p⁵ = 11 p-electrons ≠ 6. Fe: [Ar]3d⁶4s² — has 6 d-electrons ✓. Ne: 2p⁶ = 6 p-electrons ✓. So Cl (11 p-electrons) ≠ 6.
Take chapter-wise tests, track your progress, and master Atomic Structure.
Start Free Practice →