(A)Nuclear change..............
Answer:
2 electrons
Explanation:
Oxygen has 6 valence electrons and to be stable it needs 8. That means it needs 2 more electrons to have a full octet.
1. 2 H2 + O2 = 2 H2O
2. 6 K + B2O3 = 3 K2O + 2 B
3. 10 Na + 2 NaNO3 = 6 Na2O + N2
