Which one of the following sets of ions represented a collection of isoelectronic species? (Given: Atomic number: \( \mathrm{F: \, 9} \), \( \mathrm{Cl: \, 17} \), \( \mathrm{Na = 11} \), \( \mathrm{Mg = 12} \), \( \mathrm{Al = 13} \), \( \mathrm{K = 19} \), \( \mathrm{Ca = 20} \), \( \mathrm{Sc = 21} \).)