What is the deviation from aufbau principle or (n + l) rule in case of electronic configuration of La (Z = 57) ?

What is the deviation from aufbau principle or (n + l) rule in case of

1.	What is the deviation from aufbau principle or (n + l) rule in case of electronic configuration of La (Z = 57) ?
Answer» SOLUTION :One ELECTRON enters 5D before FILLING of 4f starts