Which pair of atoms forms a nonpolar covalent bond? which pair of atoms forms a nonpolar covalent bond? na and cl c and o n and cl b and o?

Types of Bonds can be predicted by calculating the difference in electronegativity.

If, Electronegativity difference is,

                Less than 0.4 then it is Non Polar Covalent

                Between 0.4 and 1.7 then it is Polar Covalent 

                Greater than 1.7 then it is Ionic

For Na and Cl,

                    E.N of Chlorine       =   3.16

                    E.N of Sodium        =   0.93

                    E.N Difference             2.23          (Ionic Bond)

For C and O,

                    E.N of Oxygen       =   3.44

                    E.N of Carbon        =   2.55

                    E.N Difference             0.89          (Polar Covalent Bond)

For N and Cl,

                    E.N of Chlorine      =   3.16

                    E.N of Notrogen     =   3.04

                    E.N Difference             0.12           (Non-Polar Covalent Bond)

For B and O,

                    E.N of Oxygen        =   3.44

                    E.N of Boron           =   2.04

                    E.N Difference             1.40          (Polar Covalent Bond)

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.