Which pair of atoms forms a nonpolar covalent bond?
a) C and S
b) C and O
c) B and O
d) Na and Cl
Solution 8SAQ Step 1 of 5 The difference of electronegativity between two elements allows us to know if two atoms are bonded with an ionic, non-polar covalent bond or polar covalent bond. If EN> 1.9 we have an ionic bond If 0.4< EN < 1.9 we have a polar covalent bond. In this case, the two atoms will share the electrons unequally, thus assuming a fractional negative charge (the atom having the higher electronegativity value) and the other a positive charge (the atom having the lower electronegativity value). If 0 < EN < 0.4 we have a non-polar covalent bond. In this case, the two atoms will share the electrons equally. We are going to demonstrate that the correct answer is a), by considering the differt electronegativity values of every couple Step 2 of 5 Letter a) Electronegativity for Carbon is 2.5, this value is the same either for Sulphur. Thus , EN=Electronegativity of Sulphur - Electronegativity of Carbon= 2.5 – 2.5= 0. This is a non polar covalent bond Step 3 of 5 Letter b) Electronegativity for Carbon is 2.5, Oxygen has a value of 3.5. Thus , EN= Electronegativity of Oxygen - Electronegativity of Carbon= 3.5 – 2.5= 1.0 . This is a polar covalent bond.