Electronic Configuration and Valence Structure of Group 16 Elements

The electronic configuration of any element is defined as the arrangement of the electrons around the nucleus. The electronic configuration of any element determines its physical state and reactivity with other elements. When one looks at the Group 16 elements, the electronic configuration of all the elements in that group is categorized by the presence of six electrons in their last shell or the valence shell. 

The elements present in group 16 consist of oxygen (0), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po). Of all the elements, only Polonium is radioactive. All these elements can exist in a free state in nature. However, due to its electronic configuration, it can react with other elements and also exists in a combined state. 

As stated earlier, electronic configuration refers to the arrangement of electrons on its orbital shells and subshells. All elements in group 16 have six electrons in its last shell; for example, the total number of electrons for oxygen is 8, which is distributed in two shells as 2 and 8. To understand the electronic distribution for other members of group 16, it is important to learn some basic principles to do so. 

The first rule is to fill the lower energy shells with electrons first before moving to the higher shells. Hund’s rule, Pauli’s exclusion principle, and Aufbau’s rule are needed to be followed while distributing the electrons. According to Pauli’s exclusion principle, no two electrons in the same atom can not have the same quantum numbers (n,l,m, and s); the first three might have the same quantum number, but it will differ from the fourth value. 

According to Hund’s rule, similar energy orbitals accommodate one electron, and then other electrons can pair with them in half-filled orbitals. According to Aufbau’s principle, electrons first occupy the lowest energy levels. All these three principles can be followed while determining the electronic configuration of an atom.

Atomic Orbital Diagonal Rule

Considering all the three above mentioned principles is the best approach for deciphering the electronic configuration of any element. For example, the total number of electrons in an oxygen atom is 8. The first step is to fill the lowest energy shell 1s with two electrons. The remaining six electrons are distributed in 2s and 2p orbitals. 2s orbital will have two electrons, and 2p orbital will have four electrons. 

According to Neil Bohr, all the members of the same group of the Periodic table have a similar electronic configuration. Therefore, it also stands true for all the members of group 16, and the electronic configuration of oxygen follows the pattern of the  general electronic configuration of group 16 elements, which is ns2 np4.

Since the noble gas is considered to have a complete electronic shell, the electronic configuration of most elements is represented in terms of its nearest noble gas.

It is important to note that the electronic configuration of any element determines its chemical properties. Group 16 electron configuration indicates that its members of Group 16 have six elements in its valence shell, and therefore require two elements to complete the octet valency. Therefore all the elements of group 16 are negatively charged since it can receive two electrons from other elements. 

These anions can interact with positively charged cations that can donate electrons so that their octet is also completed along with these anions. For example, oxygen receives two electrons, one from each hydrogen atom to form water. Sulfur receives two electrons, one from each hydrogen atom to form hydrogen sulfide gas.

About Electronic Configuration 

Students have been introduced to the atomic structure of elements in the previous classes. We all know that Atoms consist of electrons, protons and neutrons. In this class, we will get to learn about the arrangement of these subatomic particles inside the atoms of any particular element. 

The rules and principles used for determining the position of all electrons are studied under the Physical Chemistry of Class 11 NCERT textbooks. It also mentions the story of various scientists working to understand and identify the difference between various types of materials available on Earth and their properties. It is the story of the gradual development of chemistry as a subject of study. 

The electrons are the freely moving subatomic particles revolving around a nucleus centre consisting of protons and neutrons. The degree of freedom of electrons varies according to the orbit they choose for their position. Several protons present in the atoms of an element are known as the 'Atomic Number' of the element. 

This Atomic number also gives us information about the number of electrons present in the atom which are equal in number to balance the net positive charge of protons. The Periodic Table arranges the elements in the increasing order of their atomic number and categorizes all elements into different groups. Neil Bohr suggested that the elements of the same group have similar electronic configurations. 

For example, the atoms Hydrogen and Helium with single and double electrons respectively occupy the lowest valency positions. The rule and principle to arrange the electrons by assigning different orbits around the nucleus are known as the Electronic configuration of atoms. As the chemical properties of the elements depend on the number of outermost free electrons. We all know that the properties of the elements under the same group are the same so the number of electrons in the outermost cell is equal.  The Elements of group 16 such as Oxygen, Sulfur, Selenium, Tellurium, Polonium and all have 6 electrons on the outermost cell. The 's' valence shells always contain 2 electrons, The 'p' valence shell contains 4 electrons. 

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