Bohr model of Copper Atom-How to draw Copper (Cu) Bohr-Rutherford diagram?

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 The Bohr Model of Copper (Cu) has a nucleus that contains 34 neutrons and 29 protons. This nucleus is surrounded by four electron shells namely K-shell, L-shell, M-shell, and N-shell. The first shell has 2 electrons, the second shell has 8 electrons, the third shell has 10 electrons and the fourth shell has 1 electron. 

NameCopper Bohr Model
Number of neutrons34
Number of protons29
Number of electrons29
Total electron shells
Electron in the First shell(K)2
Electrons in the Second shell(L)8
Electrons in the Third shell(M)18
Electrons in the Fourth shell(N)1
Total valence electrons in Copper11

How to draw Bohr Model of Copper (Cu)?

Bohr model describes the visual representation of orbiting electrons around the small nucleus. It used different electron shells such as K, L, M, N…so on. These shells hold a specific number of electrons, the electron shell which is closest to the nucleus has less energy and the electron shell which is farthest from the nucleus has more energy.

Bohr’s diagram is very interesting and easy to draw. Here, we will draw the Bohr model of the Copper atom with some simple steps.

Steps to draw the Bohr Model of Copper atom

1. Find the number of protons, electrons, and neutrons in the Copper

Protons are the positively charged particles and neutrons are the uncharged particles, both these are constituents of the atom nuclei. Electrons are the negatively charged particles that orbit the nucleus of an atom

To find the number of protons an atom contains, just look at its atomic number.

If the atomic number of atom is 45, then proton will also be 45, if atomic number is 46, then proton will also be 46.

So, the atomic number for Copper is 29, hence, the number of protons in the Copper atom is also 29.

number of protons in copper

Now, to determine the number of neutrons in an atom, use this formula.

⇒ Number of neutrons in atom = Atomic mass of the atom(rounded to the nearest whole number) – Number of proton in an atom

For example, An atom have 33.988 atomic mass and 16 protons.

Then, to find the number of neutron, round the atomic mass to the near whole number, so, atomic mass 33.988 round to 34.

= (34 – 16 protons) = 18 number of neutrons in the atom

Now, To get the number of neutrons in a Copper atom, look at its atomic mass which is 63.54 rounded to 63, and the number of protons in Copper is 29.

∴ Hence, the number of neutrons in Copper atom = (63 – 29) = 34

number of neutrons in copper bohr model

It should be noted that “The number of electrons in a neutral atom is equal to the number of protons”.

So, the Copper atom is neutral, hence, its number of electrons will be equal to the number of protons which is 29 as we already discussed.

⇒ The number of electrons in a Copper atom = 29

⇒ The number of protons in a Copper atom = 29

⇒ The number of neutrons in a Copper atom = 34

Let’s read in detailHow to find number of protons, electrons, neutrons?

2. Draw the nucleus of an atom

A nucleus is a dense and small region that contains the number of protons and neutrons of an atom.

In this step, we have to draw a small circle that consists of a number of protons and the number of neutrons of a Copper atom.

nucleus of copper bohr model

3. Draw the First electron shell

“An electron shell may be thought of as an orbit followed by electrons around an atom’s nucleus.”

The first electron shell is also called the K-shell, this is the closest shell to the nucleus of an atom and can hold a maximum of two electrons.

As we know, the Copper atom has a total of 29 electrons. So, put two electrons from it, in the first shell, next to each other.

1st electron shell of copper

Now, that we have successfully drawn the first shell of the Copper atom that can hold 2 electrons, we know that we have used 2 electrons out of the 29 available in the first shell.

(29-2) = 27 electrons.

This shows we are left with 27 electrons that we need to accommodate in the subsequent shells of the Copper atom.

4. Draw the Second electron shell

The second shell also called the L-shell that can hold a maximum of 8 electrons. This shell is drawn after the first electron shell.

In the second electron shell, the electrons are added one at a time, starting from the top position and then going in a clockwise direction.

In second shell, electrons are added one at a time in clockwise direction as a clock position – 12 o’clock, 3 o’clock, 6 o’clock, 9 o’clock positions.

electrons placing position in bohr diagram

Once you place the electrons one at a time to each of the four sides(Top – Right – Bottom – Left], start pairing or doubling them.

As we have 27 remaining electrons of a Copper atom, out of which the second shell can hold only a maximum of 8 valence electrons.

Thus, we place the next 8 electrons of the Copper atom in the second shell. Start from the top position and put electrons one at a time, moving in a clockwise direction (Top-Right-Bottom-Left), and finally pair them up.

2nd electron shell in copper bohr diagram

At this step, out of the 29 electrons of the Copper atom, we have placed 2 electrons in the first shell and 8 electrons in the second shell.

[29 – (2+8)] = 19 electrons.

This means we are now left with 19 electrons. So let’s see how we can assign them their appropriate positions in the next shells of the Copper atom.

5. Draw the Third electron shell

The third electron shell also called the M-shell can accommodate up to 18 electrons. For the elements in the first few periods of the Periodic Table, the third shell holds up to 8 electrons only. But actually, in totality, it has the capacity to hold 18 electrons.

⇒ The third subshell exhibits this capacity of holding ‘up to 18’’ electrons for atomic numbers greater than 20 such as 21, 22, 23, 24 and so on.

⇒ This 18 electron-holding property of the third shell is specifically important for the d-block elements (Scandium to Zinc).

⇒ The M-shell is divided into subshells (s, p, and d). s can hold only 2 electrons. 6 electrons can be placed in the p-subshell. 2+6 =8, so after these 8 electrons, the rest of the electrons can be placed in the d-subshell of the third shell.

So, it is due to the presence of the d-subshell that the third shell can hold more than 8 and up to 18 electrons in total.

⇒ Another rule to keep in mind is that the filling of electrons follows the Aufbau Principle. Electrons are filled diagonally.

After completely filling the s and p subshell of shell number 3, 2 electrons are accommodated in the s-subshell of the fourth shell. Only then the remaining electrons are placed in the 3d subshell of the third shell.

aufbau principle for filling of electrons in bohr diagram of copper

⇒ But the tricky part here is that a completely filled 3d subshell with 10 electrons is more stable than a partially filled 3d subshell with 9 electrons. So instead of placing 2 electrons in 4s and the remaining 9 electrons in 3d, in a Copper atom, only 1 electron is placed in the 4s subshell while the remaining 10 electrons are situated in 3d.

In short, the Bohr model of copper contains a single electron only in the fourth shell while the third shell contains a total of 18 electrons as per the distribution of 2 electrons in 3s, 6 electrons in 3p, and 10 electrons in the 3d subshell of shell no. 3 (M-shell).

Let’s see how that’s done.

Out of the 19 electrons left of the Copper atom, we place 8 electrons in the third shell, moving in a clockwise manner as we have done for electrons in step 4.

3rd electron shell of copper bohr model

19 – 8 = 11.

As we already told you, after the 8 electrons in the third shell, we first need to place 1 electron in the fourth shell and then come back to place the remaining electrons into the third shell again.

Thus, let us place 1 electron out of the 11 left in the fourth shell first.

6. Draw the Fourth electron shell

Here, we draw the fourth electron shell and put 1 electron in it.

4th electron shell in copper

11 – 1 = 10.

We are left with 10 electrons so now we will go back and place these 10 electrons into the third shell.

7. Place the remaining electrons back into the Third electron shell

The remaining 10 electrons of Copper are placed into the Third electron shell, as shown below, again in a clockwise manner. 

electrons in 3d subshell of copper bohr diagram

Now, the 3rd shell has a total of 18 electrons.

Bohr model for Copper (Cu)

Finally, you have the accurate Bohr model of the Copper atom that contains 29 protons and 34 neutrons in the nucleus region while a total of 29 electrons circulate around the nucleus in specific orbits called shells.

The first electron shell of Copper has two electrons, there are eight electrons in the second shell, eighteen electrons in the third shell, and 1 electron is present in the fourth shell of the Copper atom.

Also Read:-

Also check :- Bohr model for all elements of Periodic table

Find the Valence electron of Copper through its Bohr diagram

From the Bohr diagram of an atom, we can easily find the number of valence electrons in an atom by looking at its outermost shell.

Now to determine the valence electrons present in the Copper atom, have a quick look at its Bohr diagram.

The Bohr diagram of Copper has four electron shells (K, L, M, N), the K-shell is the innermost shell while the outermost shell is the N-shell.

Generally, the outermost shell of an atom is also called the valence shell. According to that, definition, the electron present in the N-shell of the Copper atom is its valence electron.

The outermost shell i.e., N-shell in the Copper Bohr model contains 1 electron only hence there is technically only 1 valence electron present in the Copper atom. But the ground reality differs a bit from this ideal situation.  

∴ This is because valence electrons are alternately defined as the electrons of an atom that can participate in bond formation during a chemical reaction. 

And the transition metal (d-block) elements such as Copper (Cu) have the ability to use the electrons present in their 3d sub-shell in addition to their 4s electrons in chemical bonding.

So, as there are 10 electrons present in the 3d subshell of Cu in addition to 1 electron in its outermost shell, in this way the Copper atom is sometimes believed to have a total of 11 valence electrons.

⇒ But the most probable valencies of the Copper atom are +1 and +2   which means out of the 11 electrons available, the copper atom is most likely to use only 1 or 2 valence electrons during chemical reactions, to form Cu+1 and Cu2+ ions respectively.

This concept is known as the variable valency concept of transition metals.  But it is out of the scope of this article to discuss this concept in detail. Thus, let us move ahead.

Let’s read in detail – Valence electrons of transition metals

valence electrons in copper bohr diagram

Electron dot diagram of a Copper atom

The electron dot diagram also called Lewis’s structure of an atom represents the total valence electrons present in it.

As there are 11 valence electrons in an atom of Copper (Cu) so there are 11 dots around the Copper atom in its electron dot diagram, as shown below.

copper lewis structure

The electron configuration of Copper

Copper has an atomic number of 29 and it contains a total number of 29 electrons. From the Bohr model of Copper, we know that it has 2 electrons in the K-shell, 8 electrons in the L-shell, 18 electrons in the M-shell, and 1 electron in the N-shell.

number of electron shell in copper bohr model

So based on this electron distribution between the shells, the electronic configuration of the Copper atom is [2, 8, 18, 1].

Or the electronic configuration of Copper is [Ar] 3d104s1 since it contains a total of 29 electrons.

Also Read:-


What is the Bohr diagram?

The Bohr diagram formally called a Bohr-Rutherford model is a visual representation of orbiting electrons around the small nucleus of an atom. For example, the Bohr diagram of Copper (Cu) represents the 29 electrons present in it, revolving around the small nucleus in specific energy levels called K, L, M, and N shells.

How many electron shells the Copper Bohr model contains?

Electron shells are also called energy levels. You can find the number of electron shells for an element by knowing its period number in the Periodic Table.

The elements or atoms in the first period of the Periodic Table have one energy level or one electron shell, same as the elements in the second period have two energy levels or two electron shells, and so on.

As the Copper (Cu) atom belongs to the 4th Period in the periodic table, hence the number of electron shells for the Bohr model of Copper is also 4. There are 4 electron shells in the Copper Bohr model namely K-shell, L-shell, M-shell, and N-shell.

How many valence electrons are present in a Copper atom Bohr diagram?

The outermost shell also called the valence shell is the shell that contains the valence electrons of an atom.

According to the Bohr diagram of Copper, its outer shell is shell number 4 i.e., the N-shell containing 1 valence electron only. But the total number of valence electrons present in Copper is 11 because it can use its 3d electrons in addition to the 4s electrons during chemical bonding.

Ten 3d electrons and one 4s electron make a total of 11 valence electrons in Cu. But you should keep in mind that the Copper atom mostly uses 1 or 2 of these available valence electrons during chemical reactions.


  • The Bohr model of Copper (Cu) is drawn with four electron shells, the first shell contains 2 electrons, the second shell contains 8 electrons, the third shell contains 18 electrons and the fourth shell contains 1 electron.
  • The atomic number of Copper is 29. As Copper (Cu) is a neutral atom hence the number of protons and electrons available for its Bohr diagram are equal i.e., 29.
  • The number of neutrons for the Bohr diagram of Copper can be found by subtracting the number of protons from the atomic mass (rounded off to the nearest whole number).
  • The electron configuration of Copper in terms of the shells is [2,8,18,1] while in the standard form it is [Ar] 3d10 4s1.

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