Number of moles of dinitrogen =

14

28

= 0.05
Number of molecules in 1.4 g of dinitrogen = 0.05 × 6.022 × 1023 molecules = 0.3011 × 1023 molecules = 3.011 × 1022 molecules
Since 1 molecule of dinitrogen has 14 electrons.
∴ 3.011 × 1022 molecules of dinitrogen have = 14 × 3.011 × 1022 electrons
= 4.2154 × 1023 electrons