Diagram, Steps To Draw The Argon Bohr Model

Argon is an atomic number 18 group 18 element. Ar is a noble gas that is represented by the symbol Ar. It is also the third most abundant gas in the earth’s atmosphere. The air contains around 1.288 percent argon by mass, which can be separated via fractional distillation.

For industries, it is the principal source of argon. Argon is mostly employed in industries that require an inert atmosphere, such as titanium processing.

In this article, we’ll look at the Bohr diagram of argon and go over it step by step.

Argon Model by Bohr

The stability of electrons travelling around the nucleus could not be explained by the Rutherford model of the atom, which was proposed in 1911.

Such particles, according to classical mechanics and electromagnetic theory, could not remain stable and would lose energy.

In 1913, Niel Bohr improved on this model and presented the improvised Bohr-Rutherford atom model. He proposed that each electron moves in a pre-determined orbit with a definite size and energy in this scenario.

The atomic structure of elements is defined by the Bohr model of atom, which is a visual representation of all atomic particles, such as electrons, protons, and neutrons.

Before we get into the details of the Bohr model of the atom, it’s crucial to first grasp a few key words connected to this model’s use in explaining the structure of an atom.

• Nucleus: The atom’s nucleus, which is made up of neutrons and protons. Because of the positively charged protons, it has a positive charge.

• Protons: Protons are positively charged particles that make up an atom’s nucleus and are denoted by the sign p+.

• Neutrons: These are the neutral particles that make up an atom’s nucleus and are responsible for the majority of its physical attributes. The sign n° is used to represent them.

• Electrons: Negatively charged particles that orbit the nucleus of an atom in set circular routes. The sign e– is used to represent them.

The placement of an electron with relation to the nucleus is determined by its energy.

• Shells or orbits: The paths that electrons traverse around the nucleus are referred to as shells or orbits. Because of the difference in their energies and the capacity of the shell to accommodate the electrons, only a certain number of electrons are allowed to follow a specific orbit.

The shells of the atom in the Bohr model are designated as K, L, M, N, etc., or 1, 2, 3, 4, etc. This value rises as you get more away from the core. As the number of shells grows, so does the energy of the electrons. The shells are also known as energy levels because of this.

As a result, electrons in the K-shell, or the shell closest to the nucleus, are considered to be in the ground state, carrying the least amount of energy.

Valence electrons are electrons that are positioned in the outermost shell and have the most energy. The creation of bonds is dependent on these electrons.

Electrons can also jump from lower to higher energy levels as they gain energy or fall from higher to lower energy levels as they lose it.

There are 22 neutrons, 18 protons, and 18 electrons in an argon atom. The electrons are arranged in K, L, and M shells around the nucleus.

Argon AtomValue
No. of Proton18
No. of Neutron22
Number of Electron18
Number of shells3
Number of electrons in first (K) shell2
Number of electrons in second (L) shell8
Number of electrons in third (M) shell8
Number of valence electrons8

Drawing the Argon Bohr Model

Argon is a noble gas that belongs to Periodic Table Group 18:

The following is the information that we may obtain from the aforementioned Argon box:

• Argon has an atomic number of 18.

• Chlorine has the electronic configuration [Ne] 3s23p6.

• Ar is the chemical symbol for chlorine.

Chlorine has an atomic mass of 39.948.

We’ll now draw the Bohr atomic model for the argon atom using the information provided.

To do so, we must first determine the number of atomic species. Let’s start with the protons.

The atomic number of any atom is always equal to the number of protons in that atom.

The atomic number is 18 in the instance of the argon atom.

As a result, the number of protons = atomic number = 18 for the argon atom.

The number of neutrons in the argon atom will now be calculated.

The following is the formula for estimating the number of neutrons in an atom:

Atomic mass (rounded up to the closest full number) – number of protons = number of neutrons

Using the information from the argon box, we can now determine that argon has an atomic mass of 39.948.

We get 40 after rounding it up to the nearest whole number.

In addition, the number of protons in an argon atom is 18, as calculated above.

Now, using the above-mentioned formula, enter these values:

The number of neutrons is calculated as 40 – 18 = 22.

As a result, the number of neutrons in an argon atom equals 22.

We can now sketch the nucleus of the argon atom using the given numbers because protons and neutrons make up an atom’s nucleus. It goes like this:

Protons are represented by p+ and neutrons are represented by n° in this illustration.

We’ll now determine the amount of electrons by adding the shells to the argon nucleus.

The number of electrons in any atom is always equal to that atom’s atomic number.

As a result, when it comes to argon atoms,

The number of electrons equals the atomic number of argon, which is 18 in this case.

In addition, we will now count the number of shells as well as the amount of electrons that each shell can hold. As previously stated, each shell can only hold a certain number of electrons.

2n2, where n is the number of shells, gives the maximum number of electrons that may be held in a given shell.

We’ll calculate the number of electrons in each shell independently using this formula for the argon atom.

The maximum number of electrons in the K shell of an argon atom is 2 (1)2 = 2.

The atom looks like this once these two electrons are added to the first shell:

After that, the electrons will be added to the argon atom’s L shell.

Let’s figure out how many electrons the L shell can hold.

The maximum number of electrons in the argon atom’s L shell is 2 (2)2 = 8.

As a result, the L shell can hold up to 8 electrons.

The crucial element to keep in mind at this time is that the K shell has only two electrons that are close to each other. The arrangement pattern alters as the number of electrons grows from the L shell forward.

The electrons are now organised in a clockwise orientation in a group of four. The initial four electrons are at a 90° angle to one another. As the number of electrons grows, this angle decreases.

As a result, the first four electrons in the argon atom’s L shell are ordered as follows:

The final four electrons are introduced to the L shell in a clockwise direction.

After that, the argon atom is denoted by:

Only 8 more electrons remain, which will be housed in the M shell.

As a result, we’ll compute the maximum number of electrons that the M shell can hold.

The maximum number of electrons in the argon atom’s M shell = 2 (3)2 = 18

As a result, the M shell may accommodate a total of 18 electrons.

Because the argon atom has only 8 electrons left, we can fit them all into the M shell.

In a clockwise direction, the first four electrons will be added once more.

Finally, we achieve the Bohr model of the argon atom by adding all eight electrons to the M shell, as seen below.

As a result, the final Bohr model of the argon atom has 18 protons and 22 neutrons inside the nucleus, as well as 18 electrons orbiting around it.

The K shell has 2 electrons, the L shell has 8 electrons, and the M shell has 8 electrons.

Using the Bohr Model to Determine the Lewis Structure of Argon

The Lewis structure, also known as the electron dot structure, depicts an element’s atom and valence electrons. The nucleus is represented by the element’s atomic symbol, whilst electrons are represented by dots.

As previously stated, the argon atom’s valence shell, or M shell, has 8 electrons. As a result, the Lewis structure of argon looks like this:

Argon’s Characteristics

The following are some of argon’s most important properties:

• It was found in 1894 by Sir Ramsay.

• It’s a colourless gas that turns violet when exposed to an electric field.

• The melting and boiling points of argon are respectively 185.848 °C and 189.34 °C.

• At 0°C, the density of argon is 1.78.10-3 g.cm-3.

• Argon has a solubility in water that is similar to nitrogen but 2.5 times higher.

Conclusion

The nucleus of an argon atom, according to the Bohr model, contains 18 protons and 22 neutrons, with 18 electrons circling the nucleus.

The number of protons in an atom, as well as the number of electrons in that atom, is always equal to that atom’s atomic number.

The formula for calculating the number of neutrons is:

Atomic mass (rounded up to the closest full number) – number of protons = number of neutrons

The formula 2n2 gives the maximum number of electrons that may be held in a shell, where n is the number of shells.

The argon atom is made up of three shells: K, L, and M. The K, L, and M shells each have 2, 8, and 8 electrons.

Good luck with your studies!!

Read more: Is Air a Mixture of Homogeneous Components?

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.

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