You can find these on a periodic table
Sodium has 1 Valence Electron (1. D) because it is in group 1 on the periodic table
Magnesium has 2 Valence Electrons (2. C) because it is in group 2 on the periodic table
Oxygen has 6 Valence Electrons (3. H)
because it is group 6 on the periodic table
Nitrogen has 5 Valence Electrons (4. G)
because it is group 5 on the periodic table
Chlorine has 7 Valence Electrons (5. E )
because it is group 7 on the periodic table
Neon has 8 Valence Electrons (6. A )
because it is group 8 on the periodic table
Carbon has 4 Valence Electrons (7. F )
because it is group 4 on the periodic table
Aluminum has 3 Valence Electrons (8. B)
because it is group 3 on the periodic table
Hope this helped!