Question

how many D electrons are present in Cr 3+

Answer 1

heres your answer.............

Answer 2

Electronic configuration of cr= NOT 1s22s22p63s23p63d44s2, but 1s2 2s2 2p6 3s2 3p6 3d5 4s1.
Total d electrons =5
For cr ion cr+3=3
As removal is from outer shells first only
But filling depends on auf-bau principle