Respuesta :

Answer:

A. It formed by barium(Ba+2) ion and sulfate ( SO42- )

B. It is formed by calcium ion (Ca+2) and two fluoride ions (2F-)

C. It is formed by magnesium ion (Mg+2) and nitride ion (N3-)

D. It is formed by two potassium ions (2 K+) and oxide ion(O2-)