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What is the electron configuration for a Barium ion?    

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trueperformance | Student, Grade 10 | (Level 1) eNoter

Posted December 3, 2011 at 4:06 AM via web

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What is the electron configuration for a Barium ion?

 

 

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ncchemist | eNotes Employee

Posted December 3, 2011 at 10:44 AM (Answer #1)

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Barium is an alkaline earth metal.  This means that it is a group 2 element.  Barium's atomic number is 56; this means that it has 56 protons in its nucleus and also puts it as a period 6 element.  An uncharged barium atom would have 56 electrons also.  However as a group 2 element barium easily loses 2 electrons to form the +2 cation.  The ion has 56-2=54 electrons.  The electronic configuration is as follows:

1s2 2s2p6 3s2p6d10 4s2p6d10 5s2p6

This is a total of 54 electrons.  The uncharged barium atom would also have its 6s2 electrons for a total of 56.

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