What conditions suggested that a bond will be covalent?

A bond is likely to be covalent when two nonmetals are involved in the bonding, as they tend to share electrons to achieve a stable electron configuration. Additionally, covalent bonds typically form between elements with similar electronegativities, where the difference is small. Lastly, the absence of metal ions in the compound and the formation of molecules rather than ionic lattices also suggest a covalent bond.