Sagot :
Explanation:
1) sodium 1s 2 2s 2 2p 6 3s 1 2) iron 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 3) bromine 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 4) barium 1s 2 ...
Explanation:
1) sodium 1s 2 2s 2 2p 6 3s 1 2) iron 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 3) bromine 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 4) barium 1s 2 ...