Answer:
1. Oxygen
Total no of electrons 8
Group 6
No of valence electrons 6
Period 2
No of valence shell 2
2.Sodium
Total no of electrons 11
Group 1
No of valence electrons 1
Period 3
No of valence shell 3
3. Phosphorus
Total no of electrons 15
Group 5
No of valence electrons 5
Period 3
No of valence shell 3
