If an atom has an electron configuration of 2.8.3, how many electrons can it involve in bonding? a. 11 b. 3 c. 2 d. 13

With this an electron configuration only electrons from outer level can be involved in forming chemical bond.
B. 3 

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)