Question

The elements in group 17 of the periodic table are all called halogens. All halogens have the same

atomic number.
atomic mass.
number of possible isotopes.
number of valence electrons.

Answer 1

All halogens have the same **number of valence electrons**. Specifically, each halogen has seven valence electrons, which is characteristic of the group that determines their chemical behavior. The other options (atomic number, atomic mass, and number of possible isotopes) differ among the halogens.