Which group 17 element has stable isotopes with mass numbers 35 and 37 and representative abundances of approximately 75.77% and 24.23% respectively?

Explanation

Chlorine has the stable isotopes chlorine-35 and chlorine-37, with chlorine-35 much more abundant. The stated approximately 75.77% and 24.23% figures are representative rounded abundances, not universal constants; natural chlorine isotope composition varies. The integers 35 and 37 are mass numbers, not exact isotopic masses in u.