Which two elements are in the same period? a. hydrogen (h) and neon (ne)b. tin (sn) and antimony (sb)c. fluorine (f) and chlorine (cl)d. arsenic (as) and antimony (sb)

C. fluorine (F) and chlorine (Cl)

D. arsenic (As) and antimony (Sb)

Explanation:

In the periodic table , all the elements are arranged according to the atomic number ,

and the elements are placed in groups and periods ,

The elements with similar chemical and physical properties are placed in a common group .

The elements present in the same group have the same number of valence electrons in the valence shell  .

Hence , from the given options ,

fluorine (F) and chlorine (Cl)  belongs to group 17 with 7 valence electrons in the outermost shell .

arsenic (As) and antimony (Sb) belong to group 15 with 3 valence electrons in the outermost shell .