Answer:
C. 17
Step-by-step explanation:
The question above is related to the "Periodic Table of Elements." The Halogen group is located on the right side of the table. It consists of six elements: Fluorine, Chlorine, Bromine, Iodine, Astatine and Tennessine.
The "atomic number" of an element refers to the number of protons that can be found in the element's nucleus. Among the halogens, "Chlorine" is the only one with an atomic number of 17. Halogens do not have an atomic number of 10, 136 and 13.