a) Aluminium (Atomic number: 13)
2
2
6
2
Electronic configuration of aluminium is 1s , 2s 2p ,3s 3p
1
The orbital occupied by the ultimate electron is ‘p’. So aluminium belongs to ‘p’ block.
b) Iron (Atomic number 26)
2
2
6
2
10
2
Electronic configuration of Iron is 1s , 2s 2p , 3s 3d , 4s
The orbital occupied by the penultimate shell is‘d’. So iron belongs to ‘d’ block.
c) Cerium (Atomic number 58)
2
2
6
2
6
10
2
6
10
2
2
6
Electronic configuration of Cerium is 1s , 2s 2p , 3s 3p 3d ,4s 4p 4d 4f , 5s 5p ,
2
6s
The orbital occupied by the penultimate shell is ‘f’. So Cerium belongs to ‘f’ block.