Bohr model of Scandium atom - How to draw Scandium(Sc) Bohr-Rutherford diagram?

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The Bohr Model of Scandium (Sc) has a nucleus that contains 24 neutrons and 21 protons. This nucleus is surrounded by four-electron shells named K-shell, L-shell, M-shell, and N-shell. The first shell has 2 electrons, 2nd shell has 8, 3rd shell has 9, and 4th shell has 2 electrons.

NameScandium Bohr Model
Number of neutrons24
Number of protons21
Number of electrons21
Total electron shells
Electron in the First shell(K)2
Electrons in the Second shell(L)8
Electrons in the Third shell(M)9
Electrons in the Fourth shell(N)2
Total valence electrons in Scandium3

How to draw Bohr Model of Scandium (Sc)?

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

Steps to draw the Bohr Model of Scandium atom

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

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 Scandium is 21, hence, the number of protons in the Scandium atom is also 21.

number of protons in scandium

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 Scandium atom, look at its atomic mass which is 44.95 rounded to 45, and the number of protons in Scandium is 21.

∴ Hence, the number of neutrons in Scandium atom = (45 – 21) = 24

number of neutrons in scandium bohr diagram

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

So, the Scandium atom is neutral, hence, its number of electrons will be equal to the number of protons which is 21 as we already discussed.

⇒ The number of electrons in a Scandium atom = 21

⇒ The number of protons in a Scandium atom = 21

⇒ The number of neutrons in a Scandium atom = 24

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 Scandium atom.

nucleus of scandium 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 Scandium atom has a total of 21 electrons. So, put two electrons from it, in the first shell, next to each other.

first electron shell of scandium bohr atom

We have successfully drawn the first shell of the Scandium atom that can hold 2 electrons. As a Scandium atom has a total of 21 electrons, and from 21 electrons we have used two electrons in the first shell.

∴ (21 – 2) = 19 electrons 

Therefore, we are left with 19 electrons, let’s put them in the next shells of the Scandium 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.

So, we have 19 remaining electrons of a Scandium atom, and the 2nd shell can only hold a maximum of 8 electrons.

Therefore, put the 8 electrons of the Scandium atom in the 2nd electron shell, start from the top position, put electrons one at a time, and go in a clockwise direction(Top – Right – Bottom – Left). And, finally, pair them up.

2nd electron shell of scandium atom

As we have a total of 21 electrons for the Scandium atom and we placed 2 electrons in the first shell and 8 electrons in the second shell.

[21 – (2+8)] = 11 electrons.

This means we are now left with 11 electrons. So let’s see how we can assign them their appropriate positions in the next shells of the Scandium atom.

Let’s place it in the next shells.

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 scandium

Let’s see how that’s done.

Out of the 11 electrons left of the Scandium atom, we place 8 electrons in the third shell.

third electron shell in scandium bohr diagram

11 – 8 = 3.

As we already told you, after the 8 electrons in the third shell, we first need to place 2 electrons in the fourth shell and then come back to place the remaining electrons into the third shell again.

Thus, let us place 2 electrons out of the 3 left in the fourth shell first.

6. Draw the Fourth electron shell

Here, we draw the fourth electron shell and put 2 electrons in it. Starting from the top position, put the electrons one at a time while moving in a clockwise direction (Top-Right—Bottom-Left). Here we have only 2 electrons to put in the fourth shell, so one is placed at the top while the other is situated at the right end as shown below.

fourth electron shell in scandium bohr model

3 – 2 = 1.

We are left with only 1 electron so now we will go back and place this 1 electron into the third shell.

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

The remaining 1 electron of Scandium is placed into the Third electron shell, as shown below.

extra electron in 3d subshell of scandium

Now, the 3rd shell has a total of 9 electrons.

The third electron shell keeps on filling in the same manner in the first-row transition metals (Sc to Zn) till this shell is filled to its maximum capacity of holding 18 electrons. But we are not concerned with that in this article.

Bohr model for Scandium (Sc)

So for now, you have the Bohr model of the Scandium atom that contains 21 protons and 24 neutrons in the nucleus region while a total of 21 electrons circulate around the nucleus in specific orbits called shells.

The first electron shell of Scandium has 2 electrons, there are 8 electrons in the second shell, 9 electrons in the third shell, and 2 electrons are present in the fourth shell of the Scandium atom.

Also Read:-

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

Find the Valence electron of Scandium 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.

So, we have to find a valence electron in the Scandium atom, for this, look at its Bohr diagram.

The Bohr diagram of Scandium 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, the electrons present in the N-shell of the Scandium atom are its valence electrons.

The outermost shell i.e., N-shell in the Scandium Bohr model contains 2 electrons hence the number of valence electrons present in the Scandium atom should also be 2. 

An important point to remember is that valence electrons are also 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 Scandium (Sc) are famous for their ability to use the electrons present in their 3d sub-shell in addition to the 4s electrons in chemical bonding.

Read more – Valence electrons of transition metals

So, as there is 1 electron present in the 3d subshell of Sc in addition to 2 electrons in its outermost shell hence Scandium is actually believed to have a total of 1+2 = 3 valence electrons. But this concept is beyond the Bohr model.

valence electrons in scandium bohr diagram

Electron dot diagram of a Scandium atom

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

As there are 3 valence electrons in an atom of Scandium (Sc) so there are 3 dots around the Scandium atom in its electron dot diagram.

electron dot diagram of scandium

The electron configuration of Scandium

Scandium has an atomic number of 21 and it contains a total number of 21 electrons. From the Bohr model of Scandium, we know that it has 2 electrons in the K-shell, 8 electrons in the L-shell, 9 electrons in the M-shell, and 2 electrons in the N-shell.

number of shells in scandium bohr model

So based on this electron distribution between the shells, the electronic configuration of the Scandium atom is [2,8,9,2].

Or the electronic configuration of Scandium is [Ar] 3d1 4s2 since it contains a total of 21 electrons.

Also Read:-

FAQ

What is the Bohr diagram?

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.

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

What is the outer shell of the Bohr diagram of the Scandium 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 Scandium, its outer shell is shell number 4 i.e., the N-shell containing 2 valence electrons.

Summary

  • The Bohr model of Scandium (Sc) is drawn with four electron shells, the first shell contains 2 electrons, the second shell contains 8 electrons, the third shell contains 9 electrons and the fourth shell contains 2 electrons.
  • The atomic number of Scandium is 21. As Scandium (Sc) is a neutral atom hence the number of protons and electrons available for its Bohr diagram are equal i.e., 21.
  • The number of neutrons for the Bohr diagram of Scandium can be found by subtracting the number of protons from the atomic mass (rounded off to the nearest whole number).
  • The electron configuration of Scandium in terms of the shells is [2,8,9,2] while in the normal form it is [Ar] 3d1 4s2.

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