It occurs as a diatomic gas and is also the third most abundant element in the universe. It is a colorless and odorless gas with oxidizing properties. Oxygen is required for several processes such as combustion, cellular respiration, etc. It also forms a part of many important organic molecules such as proteins, carbohydrates, nucleic acids, etc. Plants breathe out oxygen in the environment thus, replenishing it. Hey guys!!! Our topic for today is the Bohr model of oxygen. So, if you have any questions for the same you need to read this article right to the end. Let’s begin…
Bohr Model of Oxygen
An atom is considered the smallest entity that represents matter. A number of theories were given to explain the structure of the atom. After several failed models, Ernest Rutherford, in 1911, proposed a model. This model answered almost all the questions raised by the scientific community. However, it still violated a few rules of classical mechanics and electromagnetic theory. Niel Bohr, in 1913, again modified this model and presented it as the Bohr-Rutherford model of the atom. This model overcame the shortcomings of the earlier model and is quite acceptable even today. The Bohr model explained the structure of the atom in detail along with the number and positions of all the atomic species viz. protons, neutrons, and electrons. It also threw light on the charge and stability of these entities. Now, to draw the Bohr model of the atom for the oxygen we must first understand the various atomic species and their positions inside the atom. They are: • Nucleus: Just like the sun in the solar system, it is the core of the atom. It is composed of two atomic particles i.e. protons and neutrons. • Protons: They house inside the nucleus of an atom and carry a positive charge. They are responsible for the overall charge of the nucleus. p+ is used to denote protons. • Neutrons: As the name indicates these are charge-neutral species. They also reside inside the nucleus of an atom. n° is used to denote neutrons. • Electrons: These are the extra-nuclear species that carry a negative charge. They participate in bond formation and are denoted as e–. • Shells: These are the circular paths taken by the electrons to revolve around the nucleus. Every shell has a specific amount of energy associated with it. Therefore, they are also called energy levels. The energy of the orbital increases sequentially, as we move away from the nucleus. The shells are named as 1, 2, 3, 4, etc., or as K, L, M, N, etc. from inside to outside. Also, only a fixed number of electrons can be accommodated in a particular shell. The K shell is located closest to the nucleus and has minimum energy, it is also known as the ground state for an electron. • Valence Electrons: The electrons housed in the outermost shell of an atom. These are majorly responsible for bond formation. The outermost shell is also known as the valence shell. As per the Bohr model of the atom, the electrons jump from lower to higher energy orbital as they absorb energy and also come back from higher to lower energy levels, as they release energy. The Bohr model of oxygen states that the nucleus of the oxygen atom contains 8 protons and 8 neutrons, while 8 electrons revolve around the nucleus in 2 energy levels. The K shell contains 2 electrons and the M shell contains 6 electrons. Hence, the oxygen atom has 6 valence electrons.
Steps to Draw the Bohr Model of Oxygen
The oxygen atom belongs to the 16th group of the periodic table.
The information that we can derive from the above-mentioned Oxygen box is as follows: • The atomic number of Oxygen is 8. • The electronic configuration of Oxygen is [He] 2s22p4. • The chemical symbol of Oxygen is O. • The atomic mass of Oxygen is 15.99. Using the above information we will now move on to draw the Bohr model for the oxygen atom. Before we can draw the Bohr model we must know the number of different atomic species present in an atom. To begin with, let us calculate the number of protons for the oxygen atom, The atomic number of an element represents the number of protons present in that atom. As seen in the above figure, we know that the atomic number of oxygen atoms is 8. Therefore, the number of protons in the oxygen atom is 8. Now, we will calculate the number of neutrons in the oxygen atom. The formula for determining the number of neutrons in an atom is as follows: Number of neutrons = Atomic mass (rounding it up to the nearest whole number) – Number of protons Hence, for the oxygen atom, the atomic mass is 15.99. So, rounding it up to the nearest whole number we get 16. Also, as we calculated the number of protons in the oxygen atom is 8. When we put these values in the given formula, we get, Number of neutrons = 16 – 8 = 8 Therefore, the number of neutrons in the oxygen atom = 8. As we now know the values of both the nuclear species i.e. protons and neutrons, we can draw the nucleus of the Bohr model of the oxygen atom. It appears as follows:
Here, p+ = protons and n° = neutrons In the next step, we will calculate the total number of electrons contained in the oxygen atom. The number of electrons in an atom is also determined by the atomic number of that atom As mentioned earlier the atomic number of the oxygen atom is 8. Therefore, the number of electrons in the oxygen atom is 8. Now, we will accommodate these electrons in their respective shells. For this, we will first have to calculate the number of electrons that can be accommodated in any particular shell. The maximum number of electrons for a shell can be calculated using the formula 2n2, where n is the number of shells. First of all, we will calculate the number of electrons for the first shell i.e. K shell of the oxygen atom. Number of electrons in the K shell of the oxygen atom = 2n2 = 2 (1)2 = 2. Now, we will add these two electrons to the K shell, after which it appears as follows:
Now, we will calculate the number of electrons that can be accommodated in the second shell of the atom using the same formula as above. Therefore, the maximum number of electrons that can be housed in the L shell = 2 (2)2 = 8 Hence, a maximum of 8 electrons can be accommodated in the L shell of the oxygen atom. This means that all the six electrons left with the oxygen atom will now be filled in the L shell of the atom. However, one point should be noted at this stage. In any shell that has more than 4 electrons i.e. L shell onwards, the electrons are filled in a clockwise manner in a group of four. Thus, out of the six electrons of the L shell, 4 will be filled first, in a clockwise manner, after which the oxygen atom appears as follows:
Now, the remaining two electrons will also be filled in the L shell. After placing these electrons in the L shell the Bohr model of oxygen appears as follows:
Thus, the Bohr model of the oxygen atom contains 8 protons, 8 neutrons, and 8 electrons. The protons and neutrons reside inside the nucleus while electrons revolve around the nucleus in 2 shells. The K shell contains two electrons and the L shell contains 6 electrons. With the help of this model, we can conclude that the electronic configuration of the oxygen atom is [2, 6]. Considering the molecular orbital theory, we can place these electrons in the subatomic orbital. Therefore, 2 electrons are filled in 1s orbital, 2 electrons in 2s orbital while the remaining 4 electrons are filled in 2p orbital. Hence, the final electronic configuration of the oxygen atom becomes 1s22s22p4.
Related topic you must read Chlorine Bohr Model Boron Bohr Model Lithium Bohr Model Argon Bohr Model Neon Bohr Model Sodium Bohr Model Silicon Bohr Model Phosphorus Bohr Model
Deriving Lewis Structure from Bohr Model
The Lewis structure of an atom illustrates its valence electrons around the atom. The nucleus of the atom is depicted by its atomic symbol and electrons are shown as dots around it. These diagrams are also known as electron dot structures. The Bohr model of the oxygen atom shows that oxygen contains 6 electrons in its valence shell. Hence, the Lewis structure of oxygen can be drawn as follows:
Properties of Oxygen
A few important properties of oxygen are given below: • Oxygen is a colorless gas that forms a pale blue color liquid under pressure. • The melting and boiling points of oxygen are 54.36 K and 90.2 K, respectively. • A total of 13 isotopes of oxygen are known, out of which 12O to 24O. 16O, 17O, and 18O occur naturally. • It is known to support combustion. • It is a highly reactive and oxidizing non-metal element.
Conclusion
As per the Bohr model of oxygen, it contains 8 protons and 8 neutrons in its nucleus. The oxygen atom also contains 8 electrons that revolve around the nucleus in 2 shells viz. K shell containing 2 electrons and L shell containing 6 electrons. The atomic number of an element denotes the number of protons as well as electrons in that atom. The number of neutrons in an atom can be calculated by using the following formula: Number of neutrons = Atomic mass (rounding it up to the nearest whole number) – Number of protons The maximum number of electrons allowed to be filled in a shell is given as 2n2, where n is the number of shells. In the Bohr model of the oxygen atom, 2 electrons are present in the K shell and 6 electrons are present in the L shell.
