Final answer:
The hybrid orbitals used by the nitrogen atoms are sp³ orbitals.
Step-by-step explanation:
The hybrid orbitals used by nitrogen atoms in the species given are as follows:
a. NH₃ - The nitrogen atom in NH₃ forms three sigma bonds using its three hybrid sp³ orbitals.
b. N₂F4 - The nitrogen atom in N₂F4 forms two sigma bonds using its two hybrid sp³ orbitals.
c. NF₃ - The nitrogen atom in NF₃ forms three sigma bonds using its three hybrid sp³ orbitals.
d. N₃ - The central nitrogen atom in N₃ forms three sigma bonds using its three hybrid sp³ orbitals.