Occurrence

The oxygen family, sometimes termed the chalcogens, consists of the elements found in Group 16 of the periodic table and is classified among the main group elements. It consists of the elements -oxygen, sulfur, selenium, tellurium, and polonium. These can be found in nature in both free and coupled states. Any of the seven chemical elements that comprise Group 18 (VIIIa) of the periodic table is referred to as noble gas. Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson are the elements (Og). Noble gases are colorless, odorless, and tasteless gases that are inflammable.

Group 16 elements 

The p-block elements are located on the right-hand side of the periodic table, between groups 13 and 18. Group 16 is composed of five elements: oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and polonium(Po).

The oxygen family is named after the group’s founding member. The first four elements in this group are collectively referred to as chalcogens, which means ore-forming elements, due to the fact that many metal ores are oxides and sulfides.

Occurrence of group 16 elements 

In nature, oxygen is the most abundant element. It contributes 20.946 percent of the volume of air and 46.6 percent of the mass of the earth’s crust as silicates and other compounds such as carbonates, oxides, and sulfates.

The vast majority of oxygen found in the air is created by plants through photosynthesis. Additionally, it can exist in the form of ozone.

Sulfur is the world’s sixteenth most abundant element. Sulfur is found in ore in a mixed state.

Gypsum CaSO₄.2H₂O, Epsom salt MgSO₄.7H₂O, and barytes BaSO₄ are all sulfate ores.

Galena (PbS), zinc blende (ZnS), and copper pyrites are all sulfide ores (CuFeS₂).

Sulfur is also found in a variety of biological products, including mustard, eggs, seeds, onion, wool, garlic, and hair.

Metal selenides and tellurides of selenium and tellurium are found in sulfide ores.

Polonium is a naturally occurring radioactive element.

Trends in group 16 elements 

In nature, oxygen is the most abundant element. It contributes 20.946 percent of the volume of air and 46.6 percent of the mass of the earth’s crust as silicates and other compounds such as carbonates, oxides, and sulfates. Group 16 elements have six electrons in their valence shell and have the basic electrical structure ns²np⁴.

Atomic and Ionic Radii of Group 16 Elements – The atomic and ionic radii of the elements in this group are smaller than those of group 15. As one advances along the group, the atomic and ionic radii of the elements increase.

Group 18 elements 

Helium(He), Neon(Ne), Argon(Ar), Krypton(Kr), Xenon(Xe), and Radon are all members of Group 18. (Rn). They are also known as noble or inert gases. This indicates that these elements are chemically inactive and so do not participate in any reactions.

These Elements’ Occurrence

All of these elements are present in the atmosphere in their free state. With the exception of Radon, every other noble gas is present in the atmosphere. Argon alone accounts for 0.93 percent of the atmosphere’s entire volume. This element can be prepared via fractional distillation of liquid air. Certain water springs include disintegrating gases of neon, helium, and argon. Additionally, Radon can be obtained from the disintegration of radium and thorium minerals.

Trends in the atomic properties 

Atomic Radius: The nuclear radii increase as the nuclear number decreases. This is due to the expansion of another shell at each successive element as the group descends.

Electron Gain Enthalpy: The electrical configurations of Group 18 elements are extremely stable. They have no inclination to take an electron.

They have a high ionization potential as a result of their closed electronic structures. This value drops as one moves down the group owing to nuclear size expansion.

Group 16 Elements Melting and Boiling Points- Melting and boiling points increase when the atomic size decreases from oxygen to tellurium. The enormous difference in the melting and boiling points of oxygen and sulphur could be explained by the fact that oxygen is a diatomic molecule whereas sulphur is a polyatomic molecule.

Elements of Group 16 Electronegativity- Group 16 elements have a higher electronegativity than group 15 elements. Oxygen is the second most electronegative element in the periodic table, trailing only fluorine. As one passes through the group, the electronegativity decreases. Elemental electronegativity diminishes as their atomic radii increase.

Electronic Configuration of Group 18 Elements 

The valence shell’s general configuration is ns²np⁶. Helium is an exception to this rule. It is configured as 1s². Due to the fact that they already hold the octet configuration in their valence shells, they are chemically inert. They have zero valencies.

Physical properties of group 18 elements 

Due to their stability, these elements exist as monatomic gases in their free state.

These gases are colorless, tasteless, and odiferous. These elements’ particles exhibit weak Van der Waals forces. This force increases as the group progresses downward. This is due to an augmentation in the polarising capacity of the molecules.

They have a low melting point and a low boiling point. This can be attributed to the Van der Waals forces’ weakness. As we progress along with the group, the melting and boiling points increase.

These elements can be condensed at extremely low temperatures. As the atoms’ size decreases down the group, the ease of liquefaction decreases as well.

Chemical properties of group 18 elements 

Chemically, these elements are dormant due to their stable electronic structure.

Group 18 elements have a high enthalpy of positive electron gain and high enthalpy of ionization.

The chemical mobility of group eighteen elements increases as the ionization enthalpy decreases as one moves down the group.

Helium, argon, and neon have insufficient ionization enthalpies to form compounds.

Because krypton’s ionisation enthalpy is slightly greater than that of xenon, it only forms krypton difluoride.

Conclusion 

The oxygen family consists of the elements found in Group 16 of the periodic table. Oxygen, sulfur, selenium, tellurium, and polonium can all be found in nature. Noble gases are colorless, odorless, and tasteless gases that are inflammable. The atomic and ionic radii of the elements in Group 18 are smaller than those of group 15. Argon alone accounts for 0.93 percent of the atmosphere’s entire volume.

Certain water springs include disintegrating gases of neon, helium, and argon. Radon can be obtained from radium and thorium minerals. Oxygen is the second most electronegative element in the periodic table, trailing only fluorine. These elements’ particles exhibit weak Van der Waals forces. They have a low melting point and a low boiling point due to the strength of their electrostatics.