Ionic bonding in calcium fluoride (CaF₂)

Steps:

• Calcium (group 2) has 2 outer electrons; it loses them to form Ca²⁺.
• Fluorine (group 7) has 7 outer electrons; each gains 1 to form F⁻ with a full octet.
• In CaF₂, one Ca²⁺ bonds with two F⁻ ions electrostatically.
• Diagrams show outer electrons: Ca²⁺ empty, each F⁻ with 8 electrons around nucleus.

Why C is correct:

• C depicts Ca²⁺ with no valence electrons and two F⁻ ions each with 8 valence electrons, matching ionic octet rule.

Why the others are wrong:

• A shows covalent sharing between Ca and F, violating ionic nature.
• B has only one F⁻ per Ca, incorrect for 1:2 ratio.
• D shows Ca with unpaired electrons, ignoring full ion transfer.

Final answer: C