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How to Calculate the Number of Vacancies in Copper

Electrons get built up in atoms in "shells." Each shell can hold a certain number of electrons. If a shell isn't full, the empty places are called "vacancies." There are two straightforward ways to calculate the number of vacancies in copper atoms. First, start from the known electronic structure and count the number of empty spaces in the shells. Second, look at the position in the periodic table and count the number of spaces until the shells are full.

Things You'll Need

Periodic Table

Instructions

From Electronic Configuration
- 1
  Look up the electronic configuration of copper. You will find it to be 1s2/2s2-2p6/3s2-3p6-3d10/4s1.
- 2
  Recall or look up the number of electrons required to fill each shell. You will find s shells to be complete at 2 electrons, p shells at 6, and d shells at 10.
- 3
  Recall that vacancies are defined by having the outermost s and p shells filled, and count the number of remaining slots in the 4s and 4p shells of copper. Since the 3d shell is filled, these are the only remaining vacancies. So copper has 1 electron in the 4s shell, leaving one vacancy, and no electrons in the 4p shell, leaving 6 vacancies for a total of 7.
From Position on the Periodic Table
- 4
  
  The periodic table is a map to the electronic structure of the elements.
  
  Find copper on the periodic table.
- 5
  Recall that each column on the periodic table represents the addition of one proton and one electron to the element in the previous column.
- 6
  Recall that the rightmost column represents elements with no vacancies.
- 7
  Count the number of columns from copper to the end of its row on the periodic table. This represents the number of electrons that must be added to reach a configuration with no vacancies, so it is the number of vacancies in copper. You will find seven elements from copper to krypton at the end of the row.

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