As the electronegativity difference between phosphorus and fluorine is less than 1.7 according to Pauling's Scale, they cannot form an ionic bond.
Carbon forms covalent bonds with fluorine.
yes
Fluorine
Krypton
sodium and flourine
no
Carbon forms covalent bonds with fluorine.
yes
CF2
Fluorine
Krypton
Assuming that "flourine" is intended to be "fluorine", the answer is no. Both carbon and fluorine are unlikely to be electron donors and therefore form a covalent bond instead, so that both of these non metals can share electrons.
You are most likely referring to ClF (with a lowercase L). This compound contains chlorine and fluorine.
No, they form a covalent compound because there is not a great enough difference in electronegativity for one element to completely pull the electrons away from the other.
Krypton (Kr)
Lithium
Yes. They will form the ionic compound magnesium fluoride, MgF2.