posted by billy a. .
Which of the following is a stable ion or are stable ions?
Your question doesn't make sense to me. Z is not an ion. And Na+1 and Ca+2 exist but ONLY in compounds such as NaCl or CaO. Both Na+1 and Ca+2 are very reactive; therefore, you usually see them only combined with a negative ion.
sorry i meant zn -2
No such thing as Zn-2. There is a Zn+2