Past exam of the chemistry A course of the University of Cambridge / 2021 / Paper 1 / A4 / a / ii / Solution

In the C3v point group, the nitrogen valence atomic orbitals transform asThe $s$ orbital is invariant under every symmetry operation; $p_z$ is also invariant because each operation preserves the $z$ coordinate. The other two components mix as a two-dimensional irreducible representation.