Answer:
Step-by-step explanation:
An anion is a negatively charged atom ie. Atoms that have gained an electron.
Flouirne is a group 7 element and it is highly electronegative. It easily draws electron to itself. With an electron, the outermost shell of Flouirne would mimic that of a noble gas.
Therefore, a combination of Sr and F would make F an electron acceptor and then an anion.