Electron Configurations for First 20 Elements (using Aufbau)

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Detailed Solution

Here are the ground-state electron configurations for the first 20 elements, following the Aufbau principle. The noble gas shorthand is provided in brackets for efficiency.

Element (Symbol, Z)	Full Configuration	Noble Gas Shorthand
1. Hydrogen (H, Z=1)	`1s¹`	---
2. Helium (He, Z=2)	`1s²`	`[He]`
3. Lithium (Li, Z=3)	`1s² 2s¹`	`[He] 2s¹`
4. Beryllium (Be, Z=4)	`1s² 2s²`	`[He] 2s²`
5. Boron (B, Z=5)	`1s² 2s² 2p¹`	`[He] 2s² 2p¹`
6. Carbon (C, Z=6)	`1s² 2s² 2p²`	`[He] 2s² 2p²`
7. Nitrogen (N, Z=7)	`1s² 2s² 2p³`	`[He] 2s² 2p³`
8. Oxygen (O, Z=8)	`1s² 2s² 2p⁴`	`[He] 2s² 2p⁴`
9. Fluorine (F, Z=9)	`1s² 2s² 2p⁵`	`[He] 2s² 2p⁵`
10. Neon (Ne, Z=10)	`1s² 2s² 2p⁶`	`[Ne]`
11. Sodium (Na, Z=11)	`1s² 2s² 2p⁶ 3s¹`	`[Ne] 3s¹`
12. Magnesium (Mg, Z=12)	`1s² 2s² 2p⁶ 3s²`	`[Ne] 3s²`
13. Aluminum (Al, Z=13)	`1s² 2s² 2p⁶ 3s² 3p¹`	`[Ne] 3s² 3p¹`
14. Silicon (Si, Z=14)	`1s² 2s² 2p⁶ 3s² 3p²`	`[Ne] 3s² 3p²`
15. Phosphorus (P, Z=15)	`1s² 2s² 2p⁶ 3s² 3p³`	`[Ne] 3s² 3p³`
16. Sulfur (S, Z=16)	`1S² 2s² 2p⁶ 3s² 3p⁴`	`[Ne] 3s² 3p⁴`
17. Chlorine (Cl, Z=17)	`1s² 2s² 2p⁶ 3s² 3p⁵`	`[Ne] 3s² 3p⁵`
18. Argon (Ar, Z=18)	`1s² 2s² 2p⁶ 3s² 3p⁶`	`[Ar]`
19. Potassium (K, Z=19)	`1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹`	`[Ar] 4s¹`
20. Calcium (Ca, Z=20)	`1s² 2s² 2p⁶ 3s² 3p⁶ 4s²`	`[Ar] 4s²`