Answer: The nonpolar covalent bond happens in an O₂ molecule.
Explanation: Nonpolar bonds happen where there's no difference between the polarity of the atoms involved. This usually happens when the same atoms bond to each other, which explains why the O₂ molecule is the one who has this bond.
Number of moles = mass of Ni /molecular mass of Ni
mass of nickel = 86.4 g
molecular mass of nickel = 58.69
number of moles of Ni in 86.4 g
=86.4/58.69
=1.472 mol
(rounded to four significant figures instead of three because the first digit of the answer starts with a 1).
The answer is in the attachment below: