Answer: 2 : 1
Explanation:
Cation :
Ca - calcium = atomic number = 20
Electron dot configuration : 2, 8, 8, 2
Ca losses 2 electrons in its outermost shell and thus has a charge of 2+ in other to attain a stable octet state.
Anion:
F - has 7 valence electrons and thus needs 1 electron to achieve a stable octet state, hence it accepts one electron has has a charge of (-1)
Therefore,
Ratio of cation (+) to negative (-) = 2 :1
