Question

why does 5d orbital get filled first before 4f ?

Answer 1

according to aufbau principle 1s<2s<2p<3s<3p <4s<3d<4p......orbits fill.in order of energy so 5d fills before than 4f .the nuclear charge is less in 4f orbitals.and lower their energy well before the 5d .i hope it helps u .plzz mark me as brainliest.☺