the elements in group 17 of the periodic table are all called halogens. all halogens have the same\no atomic…

the elements in group 17 of the periodic table are all called halogens. all halogens have the same\no atomic number.\no atomic mass.\no number of possible isotopes.\no number of valence electrons.
Answer
Brief Explanations:
Elements in the same group of the periodic table have the same number of valence - electrons. Halogens in group 17 all have 7 valence electrons. Each element has a unique atomic number and atomic mass. The number of possible isotopes varies among elements.
Answer:
D. number of valence electrons