Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable metal with fair electrical and thermal conductivity.
Like all metals, copper atoms have a filled valence band of electrons that are bound to the atom. These electrons play a role in determining the atom’s properties.
Because copper is at atomic number 29, it has one electron in its valence band. This means that there are only two electrons that contribute to the electronic configuration of the atom. The electron configuration for copper is [Ar] 3d104s2.
Cu has an electron configuration of [Ar] 3d104s2, where Ar represents the argon isotope with atomic number 36 and 3d104s2 represents the number of electrons in each orbital and spin. Changing this electron configuration for Cu requires adding or removing Electrons, Orbital s , or Spins .
Use the noble-gas shorthand
When describing the electron configuration of a chemical element, using the noble-gas shorthand is a quick and easy way to get the right answer. This is a very useful tool to have in your pocket when it comes to chemistry!
You can only use this shorthand if the chemical element in question is in the same column of the periodic table as the noble gases. Since copper is one spot down from helium on the table, we can use helium’s electron configuration as a starting point for copper.
The number of protons in an atom determines its chemical behavior, which means that atoms of different elements with the same number of electrons will behave similarly. By giving each electron a position in order starting at 1s, 2s, 3s, etc., you can determine an atom’s ground state electron configuration.
To give the ground-state electron configuration for copper (Cu), start with its chemical equivalent, gallium (Ga). Gallium has three valence electrons, so Cu must have four valence electrons.
Number the shells starting at 1
Now that you can write the electron configuration for copper, you can add electrons to copper to make other metals. To add an electron, you need to provide it with a shell that is empty and matches its intrinsic property.
For example, if a shell is 2s2, it can accommodate two electrons with s-electron properties. To add an electron to copper, provide it with a 2s electron and it will be stable.
This is why there are many metals within the same column on the periodic table. They all have a different number of shells and intrinsic properties, so they all require different shells to be filled in order to be stable.
List the valence electrons starting at 1
Now that you know how to write the ground-state electron configuration for a single atom, you can do the same for atoms that bond!
Atoms can bond through ionic or covalent bonds. Ionic bonds are formed when atoms have opposite charges, and they are characterized by having fixed valence shells.
For example, in sodium chloride (NaCl), the atom of sodium has a 1+ charge, so it can only accept 1 electron in its outermost shell to be neutral. Chlorine has a -1 charge, so it can give up 1 electron in its outermost shell to be neutral. When these two atoms bond, they form an ionic compound where each atom keeps its own identity.
In contrast, covalent bonds are characterized by sharing electrons. To write the electron configuration for an atom in a molecule using noble-gas shorthand, start with the element with the lowest atomic number and list its valence electrons starting at 1. Then go to the next lowest atomic number and do the same until all of the atoms in the molecule are listed.
Choose a noble gas to match each shell
Now that you know how to give the ground-state electron configuration for a single element, you can use that knowledge to assign electrons to an atom in a compound.
Compounds are composed of at least two different elements. In this case, copper is connected to oxygen, so you need to add electrons to the Cu atom and take them away from the O atoms.
To do this, start by choosing a noble gas that fills one of the shells. In this case, choose Ne because it fills the second shell. Then, write out its electron configuration using shorthand.
Next, add your new electrons between the already existing ones using more shorthand.
Fill in the electron configuration chart with dots and parentheses
Now that you know how to write the electron configuration for copper, let’s put that knowledge to use!
To give the ground-state electron configuration for copper, we will first write out the full orbital number and then fill in the dots and parentheses in order.
For example, let’s use the noble-gas shorthand to write out the ground-state electron configuration for copper. We will first write out the full number of electrons in each orbital, then fill in the dots and parentheses in order.
First, we will write out all of the inner electrons. So start by writing out one inner electron in s-subshell 1s2. Then, add a pair of parentheses and write 2s22p6. Next, add a pair of parentheses and write 2p6.(7) Finally, add a single dot to make it 1s22p6.(2p6)7.
Match up the dots and parentheses for each shell
Now that you can give the electron configuration for copper, you will learn how to use noble-gas shorthand to give the ground-state electron configuration for a molecule.
To do this, you will need to know the number of electrons in each shell of a copper atom and how many shells it has. You will also need to know the number of electrons in each shell of each noble gas.
First, determine which shell(s) contain 8 electrons. Since copper is in the column family, its outermost shell is going to contain 8 electrons. Copper needs to match up these 8 electrons with the 8 electrons in a neutral atom of a noble gas.
You can do this by taking one electron from each shell and giving it to the next innermost shell until all shells contain 8 electrons. Once you have done this, give your molecule an electron configuration that matches up with an atom of a noble gas.
Check your work by looking at the orbital diagrams
Once you have completed the noble-gas shorthand for electron configuration, the next step is to check your work. You can do this by looking at the orbital diagram for copper.
The orbital diagram shows you all the possible electron configurations and how many electrons are in each one. You can see which orbitals are filled and which are not, as well as how many electrons are in each orbital.
By looking at the orbital diagram for copper, you can see that it has one s-orbital filled with two electrons, one p-orbital filled with three electrons, and one d-orbital filled with ten electrons. These twelve electrons fill the 12 available electron shells in copper.
You can also see that there are no inner shell vacancies, which would indicate anions rather than atoms.
Practice with more examples
Now that you have learned how to give the ground-state electron configuration for metals using noble-gas shorthand, you can use this knowledge to practice more.
There are many other metal atoms that you can give their electron configurations with this method. You can even try giving the configurations for some nonmetals!
Some websites that offer many examples are Chemdoodle, Google Docs, and Reddit. The last one offers a thread called PhysicsForums where people post problems they have solved and ask for feedback.
This is a great way to help others and gain feedback on your solving skills. By solving others’ problems, you can test your own ability to give the electron configuration of a atom.