Which type of reaction occurs when nonmetal atoms become negative nonmetal ions?
a. oxidation
b. reduction
c. substitution
d. condensation

The answer is B. reduction. The atom becoming negative ions means it gains electrons. The reaction which gain electrons is reduction reaction. So the answer is B.

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.