Page 8 - classification of elements

Electronic configuration of chromium:

atomic no: 24

• 1s 2

2
• 1s 2s 2

2
2
• 1s 2s 2p 6

2
6
2
• 1s 2s 2p 3s 2
2
2
2
6
• 1s 2s 2p 3s 3p 6
6
2
4
2
6
2
2
• 1s 2s 2p 3s 3p 4s 3d but it is special case where d sub-shell is stable being
either half filled (i.e with 5 electron) or full filled (i.e with 10 electrons so the
4
2
th
outer most 4 shell (4s ) gives one electron to inner sub-shell (3d ) and becomes
stable.

1
6
2
2
2
6
•1s 2s 2p 3s 3p 4s 3d 5