# Bohr model of Krypton Atom-How to draw Krypton (Kr) Bohr Rutherford diagram?

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• The Bohr Model of Krypton (Kr) has a nucleus that contains 48 neutrons and 36 protons.
• This nucleus is surrounded by four electron shells namely K-shell, L-shell, M-shell, and N-shell. The 1st shell has 2 electrons, the 2nd shell has 8 electrons, the 3rd shell has 18 electrons and the 4th shell contains 8 electrons.
 Name Krypton Bohr Model Number of neutrons 48 Number of protons 36 Number of electrons 36 Total electron shells 4 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) 8 Total valence electrons in Krypton 8
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## How to draw Bohr Model of Krypton (Kr)?

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 Krypton atom with some simple steps.

## Steps to draw the Bohr Model of Krypton atom

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

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 Krypton is 36, hence, the number of protons in the Krypton atom is also 36.

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 Krypton atom, look at its atomic mass which is 83.798, rounded off to the nearest whole number it is 84. The number of protons present in Krypton is 36.

∴ Hence, the number of neutrons in Krypton atom = (84 – 36) = 48.

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

As the Krypton (Kr) atom is neutral thus the number of electrons present in it will be equal to its number of protons i.e., 36, as we discussed earlier.

⇒ The number of electrons in a Krypton atom = 36

⇒ The number of protons in the Krypton atom = 36

⇒ The number of neutrons in a Krypton atom = 48

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 Krypton atom.

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 identified, the Krypton atom has a total of 36 electrons. So we need to put 2 electrons from the 36 available in the first shell, next to each other, as shown below.

Now, that we have successfully drawn the first shell of the Krypton atom that can hold 2 electrons, we know that we have used 2 electrons out of the 36 available in the first shell.

(36-2) = 34 electrons.

This shows we are left with 34 electrons that we need to accommodate in the subsequent shells of the Krypton 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.

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 34 remaining electrons of a Krypton 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 Krypton 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.

At this step, out of the 36 electrons of the Krypton atom, we have placed 2 electrons in the first shell and 8 electrons in the second shell.

[36 – (2+8)] = 26 electrons.

This means we are now left with 26 electrons. So let’s see how we can assign them their appropriate positions in the next shells of the Krypton 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, 25, 26, and so on.

⇒ The atomic number of Krypton (Kr) is 36. As 36 is visibly greater than 20, this means the M-shell in the Krypton Bohr model will be filled to its maximum capacity by accommodating a total of 18 electrons, as shown below.

The electrons are placed in a clockwise manner, as we discussed in step 4. Starting from the top position, put the electrons one at a time while moving in a clockwise direction (Top-Right—Bottom-Left), before pairing up the electrons.

By the time we have reached this step, out of the 36 electrons of the Krypton atom, we have placed 2 electrons in the first shell, 8 electrons in the second shell and 18 electrons in the third electron shell which means a total of 2+8+18 = 28 electrons are used so far.

36 – [ 2+ 8+ 18] = 36 – 28 = 8 electrons.

Thus, the remaining 8 electrons then go into the fourth shell of the Krypton Bohr model.

6. Draw the Fourth electron shell

The 8 electrons are filled in the Fourth electron shell of the Krypton Bohr model, again following the clockwise pattern of placing electrons, as shown below.

Now, this shell has a total of 8 electrons.

And here we have the accurate Bohr model of the Krypton (Kr) atom that contains 36 protons and 48 neutrons in the nucleus region while a total of 36 electrons circulate around the nucleus in specific orbits called shells.

The first electron shell of Krypton has two electrons, there are eight electrons in the second shell, eighteen electrons in the third shell, and 8 electrons in the fourth shell of Krypton (Kr).

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

## FAQ

### 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 Krypton (Kr) represents the 36 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 Krypton 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, similarly, the elements in the second period have two energy levels or two electron shells, and so on.

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

### What is the outer shell of the Bohr diagram of the Krypton atom?

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 Krypton, its outer shell is shell number 4 i.e., the N-shell containing 8 valence electrons.

A stable octet electronic configuration marks the extraordinary stability of the Krypton (Kr) atom and it is because of this reason that Krypton is an inert element called a Noble gas situated in Group VIII A of the Periodic Table.

## Summary

• The Bohr model of Krypton (Kr) 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 8 electrons.
• The atomic number of Krypton is 36. As Krypton (Kr) is a neutral atom hence the number of protons and electrons available for its Bohr diagram are equal i.e., 36.
• The number of neutrons for the Bohr diagram of Krypton can be found by subtracting the number of protons from the atomic mass (rounded off to the nearest whole number).
• The electron configuration of Krypton in terms of the shells is [2, 8, 18, 8] while in the standard form it is [Ar] 3d10 4s2 4p6.

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