According to the theory of stellar interiors, one possible fusion reaction in massive aging stars is 12C6 + 12C6 → 20Ne10 + 4He2

Required:
a. What is the Q-value of the reaction in MeV?
b. What is the threshold energy of the reaction in MeV?

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

Hbr dissociates to form h+ and br-ca(oh)2 dissociates to form ca2+ and 2oh-the h+ and oh- react to form waterassuming the reactants are dissolved in water, the net reaction is h+ + oh- —> h2oif you’re asked to show all components of the reaction, the complete reaction is 2hbr + ca(oh)2 —> cabr2 + 2h2o

Provide more information for : )

The answer is the third choice