What is the geometry of nitrogen atom in NH3, N(CH3)3 and N[Si(CH3)]3 molecules?I : Trigonal PlanarII : Trigonal PYramidalIII : Square Planar

In case of NH3 : Trigonal pyramidal due to lp-bp repulsion. N(CH3)3 : same as in NH3 but in case of N[Si(CH3)3] it isplanar. It is due to the fact that lone-pair on N-atom is transferred to the empty d-orbitals of silicon (pπ-dπo verlapping) and its Lewis base character is lost.