Answer:
Sodium (Na): Atomic no. 11
- Configuration: 1s² 2s² 2p⁶ 3s¹
Magnesium (Mg): atomic no. 12
- Configuration: 1s² 2s² 2p⁶ 3s²
Aluminum (Al): atomic no. 13
- Configuration: 1s² 2s² 2p⁶ 3s² 3p¹
Silicon (Si): Atomic no. 14
- Configuration: 1s² 2s² 2p⁶ 3s² 3p²
Phosphorus (P): Atomic no. 15
- Configuration: 1s² 2s² 2p⁶ 3s² 3p³
Sulfur (S): Atomic no. 16
- Configuration: 1s² 2s² 2p⁶ 3s² 3p⁴
Chlorine (Cl): Atomic no. 17
- Configuration: 1s² 2s² 2p⁶ 3s² 3p⁵
From the above electronic configuration, it's clear that none of the elements have complete outer shells.
