CHEMISTRY HELLLPPPPP

If two letters (that represent elements) are next to each other in the mnemonic "FONClBrISCH", are they polar covalent? Or what? Please explain! Thank youuu~

fluorine, oxygen, nitrogen, chlorine, bromine, iodine, sulfur, carbon, hydrogen
it depends upon the electronegativities of each element
F-O = polar covalent (pc)
O-N = pc
N-Cl = nonpolar covalent (npc)
Cl-Br = npc
Br-I = pc
I-S = pc
S-C = npc
C-H = npc

omoom i hate chem what the heck is this