I believe the answer is a because 2 times 12 is 24. Hope this helped
Answer:
Fr
Explanation:
Francium (Fr) has the lowest ionization energy, with a value of 4.0727eV. This ionization energy increases as one advances in a period, being greater in the group of nonmetals.
the answer is 15.
4+4+4+1 =13 then u add the 2 outside the bracket which will give u 15