Which of the following are likely to form a covakent bond

For the most part, non-metals (excluding Nobel gases) are the most likely to form covalent bonds. Pure covalent bonds are formed between atoms with the same electronegativity, ie. they are trying to hold on to the electrons in the bond with the same strength.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

5.6⋅10−^19  j

do you need the explaination?