How many electrons are shared in a triple bond between two nitrogen atoms?
The concept of a shared electron should trigger in your memory the concept of a covalent bond. The “co” in covalent indicates that electrons are shared. And “valent” refers to valency or the outer shell of electrons. So covalent indicates a situation where the outer shell electrons of atoms are shared. The question refers to a triple bond between two nitrogen atoms. This is how you might draw a molecule of nitrogen with a nitrogen nitrogen triple bond.
But what does this three-line bond really mean? This is the electron shell diagram for nitrogen. An atom of nitrogen has two core electrons and five valence electrons. This electron configuration can be written 2,5. When we consider the bonding in a nitrogen molecule, we look only at the valence shells of the nitrogen atoms. The outer shell of nitrogen can accommodate a total of eight electrons.
So, to achieve the most stable configuration, the nitrogen atoms share three electrons each in the triple bond. This can be represented in the dot and cross diagram like so, or this way in the Lewis diagram. Either way, we’re depicting six shared electrons between the two nitrogen atoms in the triple bond. This brings the valence shells of both atoms up to their maximum occupancy of eight electrons.
Of course this question could have been answered without referring to the nitrogen atoms at all and simply going back to the definition of a triple bond. For instance, in a single covalent bond, there are two shared electrons. In a double covalent bond, there are four shared electrons. And in a triple bond, there are six shared electrons. So the answer to our question, how many electrons are shared in a triple bond between two nitrogen atoms, is six.