When you go to the D's you go back... So it'd be :

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^2

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^2

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^2

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 4d^10 4p^6 5s^2 5d^2

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