Group 16 Elements

Group 16 Elements refer to those elements which are arranged in the 16^th group of the Modern Periodic Table. Group 16 accommodates five elements in total from the second to sixth period. If we carefully observe the periodic table, we find that in the case of Group 16 Elements, the last electrons enter the p-orbital and hence the Group 16 Elements are also called p-block elements. Also, Group 16 is located on the left side of the periodic table. Group 16 Elements are primarily non-metal in nature. The p-block extends from Group 13 to Group 18. The p-block does not include helium, which is found at the top of column 8A. The p orbital can only store six electrons, which is why the p-block has six columns. The p-block is the only block that contains all three categories of elements: metals, nonmetals, and metalloids, and it has the greatest diversity of elements. In this article, we will learn about the Group 16 Elements, their electronic configuration and properties in detail.

What are Group 16 Elements?

The elements that belong to the 16th Group in the Modern Periodic Table are called Group 16 Elements. There are Five Elements in Group 16, these are Oxygen, Sulphur, Selenium, Tellurium and Polonium. The Group 16 Elements are p-block elements as the last electrons enter the p-block. Group 16 Elements are known as Chalcogens because the ores the Copper (Greek Name ‘Chalkos’) are in the form of Oxide or Sulfide with traces of Selenium and Tellurium in it.

The period, atomic number and symbols of Group 16 elements are tabulated below:

Period	Atomic Number	Elements	Symbols
2	8	Oxygen	O
3	16	Sulphur	S
4	34	Selenium	Se
5	52	Tellurium	Te
6	84	Polonium	Po

Oxygen

Oxygen is represented by the chemical symbol O. It is a colourless, odourless gas that is transformed into carbon dioxide during the human respiration process and produced during photosynthesis. Oxygen is the second most abundant gas percentwise in the atmosphere. Oxygen is the most important gas for the survival of living organisms. The molecule of oxygen is a diatomic molecule (O₂). In traces, oxygen may also be found as a triatomic molecule (O₃), which is known as Ozone. Many elements mix easily with oxygen. The ores of most of the elements exist in the form of Oxide. The evolution of heat energy occurs with the combining of particular components, and this process is known as combustion.

Sulphur

Sulphur is represented by the letter S. Its atomic number is 16 and its atomic mass is 32u. It is yellow in colour, tasteless and odourless. milIt is a non-metal that comes in ninth place in terms of cosmic abundance. Sulphur atoms make up around one in every 20,000-30,000 atoms. Sulphur may be found in both the combined and free states. Seawater contains around 0.09 percent sulphur in the form of sulphates. A high amount of sulphur is found in subsurface deposits of pure sulphur present in dome-like formations, and the meteorite contains 12 percent sulphur. The activity of anaerobic bacteria on sulphate minerals such as gypsum produces sulphur. They have multiple oxidation states from -2 to +6. The oxides of Sulfur exist as SO₂ and SO₃.

Learn More, Allotropes of Sulphur and Oxides of Sulphur

Selenium

Selenium is more scarce than either oxygen or sulphur. In a few minerals, it can be found both free and associated with heavy metals (such as lead, silver, or mercury). Under typical settings, the grey metallic form of selenium is the most stable form of the element. The properties of Selenium are almost similar to Sulfur. Selenium is widely used in semiconductor industries for the manufacturing of rectifiers.

Tellurium

Tellurium is a chemical element with the atomic number 52 that possesses characteristics that are similar to both metals and non-metals. It’s one of the most uncommon stable elements on the planet’s surface. Tellurium is metalloid in nature and is used in solar panels and memory chips. It’s commonly found in free form and in compounds with other elements including copper, lead, silver, and gold.

Polonium

Among the group 16 elements, it is the rarest. It’s a radioactive substance. Polonium is occasionally utilised for alpha radiation for scientific purposes. Polonium has two allotropes which are metallic in nature. Polonium is used to form synthetic compounds in laboratories but its compound is not found in nature. Polonium is highly toxic in nature.

Occurrence of Group 16 Elements

• The element oxygen is the most prevalent in nature. As silicates and other compounds such as carbonates, oxides, and sulphates, it contributes 20.946 percent of the volume of air and 46.6 percent of the earth’s crust by mass.
• The vast majority of oxygen in the air is produced by photosynthesis in plants. It can also be present in the form of ozone.
• Sulphur is the sixteenth most common element on the planet. Sulphur is present in ore in its mixed condition.
• Sulphate ores include gypsum CaSO₄.2H₂O, Epsom salt MgSO₄.7H₂O, and barytes BaSO₄.
• Sulphide ores include galena (PbS), zinc blende (ZnS), and copper pyrites (CuFeS₂).
• Sulphur may also be present in mustard, eggs, seeds, onion, wool, garlic, and hair, among other biological compounds.
• Sulphide ores contain metal selenides and tellurides of selenium and tellurium.
• Selenium occurs in Earth’s Crust in traces 90 parts per Billion.
• Tellurium occurs in 0.001 parts per million.
• Polonium is a radioactive element that occurs in nature.

Trends in Group 16 Elements

• Electronic Configuration of Group 16 Elements- Group 16 elements have six electrons in their valence shell and have the basic electrical structure ns²np⁴.

Elements	Atomic Number	Electronic Configuration	Group Number	Period Number
Oxygen	8	[He] 2s2 2p4	16	2
Sulphur	16	[Ne] 3s2 3p4	16	3
Selenium	34	[Ar] 3d10 4s2 4p4	16	4
Tellurium	52	[Kr] 4d10 5s2 5p4	16	5
Polonium	84	[Xe] 4f14 5d10 6s2 6p4	16	6

• Atomic and Ionic Radii of Group 16 Elements: The atomic and ionic radii of the elements in this group are less than those of the elements in Group 15 because of increased nucleic charge. The atomic and ionic radii of the elements grow as one progresses down the group due to the addition of a new valence shell.
• Group 16 Elements Ionisation Enthalpy: The ionisation enthalpy of the elements in this group is lower than that of the elements in group 15. The ionisation enthalpies of the elements decrease as one proceeds down the group. The second ionisation enthalpies of members of group 16 are greater than those of members of group 15. This is because the second electron must be taken from a more symmetrical half-filled state, which is more stable after the first electron is removed.
• Electron Gain Enthalpy of Group 16 Elements: As the atomic size grows down the group, the electron gain enthalpy falls. Oxygen’s electron gain enthalpy is less negative than sulphur’s. Oxygen has a higher repulsion between the electrons already present and the incoming electron due to its compact structure. Because of these electron-electron repulsions, the oxygen atom is less likely than the sulphur atom to receive the additional electron.
• Melting and Boiling Points of Group 16 Elements: From oxygen to tellurium, the melting and boiling points increase as the atomic size decreases. The large disparity in melting and boiling temperatures between oxygen and sulphur might be due to the fact that oxygen is a diatomic molecule whereas sulphur is a polyatomic molecule.
• Group 16 Elements Electronegativity: The electronegativity values of group 16 elements are greater than those of group 15. Oxygen is the second most electronegative element, behind fluorine. The electronegativity diminishes as one progresses along with the group. The electronegativity of elements decreases as their atomic radii rise.
• Metallic Character of Group 16 Elements: The group becomes more metallic as we move down the group. Non-Metals oxygen and sulphur are the first two elements. Metalloids such as selenium and tellurium, as well as polonium, are metals.
• Catenation of Group 16 Elements: Catenation is the capacity of an atom to construct a lengthy chain structure by making bonds with identical atoms. In this category, only sulphur has a strong proclivity for catenation. This tendency is also seen in oxygen but to a lesser amount.
• Elemental State of Group 16 Elements: The molecule of oxygen is a diatomic molecule. It takes the shape of a gas. An oxygen molecule has a pπ–pπ overlap between two oxygen atoms, producing a double bond, O=O. Oxygen exists as gas because its intermolecular interactions are less than Van der Waals forces. The family’s remaining members lack stable pπ–pπ bonds and do not exist as diatomic molecules. Single bonds join the other atoms, resulting in polyatomic complex compounds.

Allotropy of Group 16 Elements

Allotropy refers to the different forms of elements which have different physical properties but similar chemical properties. The allotropes for Group 16 Elements are discussed below:

• Dioxygen and ozone are two forms of oxygen.
• Sulphur comes in yellow ortho-rhombic,  α and β monoclinic forms.
• There are eight allotropes of selenium, three of which are red monoclinic forms with Se₈ rings. The thermodynamically stable form of selenium is grey hexagonal metallic selenium with polymeric helical chains. Amorphous black selenium is the most prevalent form of the element. The only selenium allotrope that conducts electricity is grey selenium.
• There is just one crystalline form of tellurium, which has a chain structure similar to grey selenium.
• Polonium has 33 isotopes and all exhibit radioactivity.

Oxidation States of Group 16 Elements

The outer shell configuration of group 16 elements is ns²np⁴, and they can acquire noble gas configuration by acquiring two electrons, producing the M^-2 ion, or by sharing two electrons, establishing two covalent bonds. As a result, both negative and positive oxidation states are represented by these elements. The oxidation states of the elements in group 16 are 2, +2, +4, and +6.

Elements	Atomic Number	Electronic Configuration	Oxidation State
Oxygen	8	[He] 2s2 2p4	-2,-1,+1,+2
Sulphur	16	[Ne] 3s2 3p4	-2,+2,+4,+6
Selenium	34	[Ar] 3d10 4s2 4p4	-2,+2,+4,+6
Tellurium	52	[Kr] 4d10 5s2 5p4	-2,+2,+4,+6
Polonium	84	[Xe] 4f14 5d10 6s2 6p4	+2,+4,+6

Anomalous Behaviour of Oxygen

The attributes of the group’s major element differ from those of the other components in general. The characteristics of oxygen are distinct from those of the other elements in the group. The extraordinary qualities of oxygen are attributed to Because of the following factors:

• Its tiny nuclear size, high ionisation enthalpy or electronegativity
• High ionisation enthalpy or electronegativity
• Lack of d-orbitals.

Points of Difference between Oxygen and Other Members

• Oxygen is a diatomic gas, whereas others are complicated solids.
• Oxygen is very nonmetallic due to its strong electronegativity.
• Other members’ di-negative anions are less abundant; oxygen is quickly transformed into an O^2– ion.
• Because the two atoms are bound together by very strong multiple bonds with high bond energy, the oxygen molecule is extremely stable. As a result, under typical settings, conventional oxygen is inactive.
• The oxygen molecule is paramagnetic and possesses two unpaired electrons in its gaseous, liquid, and solid phases. The remainder is diamagnetic.

Physical Properties of Group 16 Elements

The Physical Features of Group 16 Elements are mentioned below:

Elements	Atomic Mass	Colour	Nature	Melting Point	Boiling Point	Density (g/cm3)
Oxygen	16	Colourless	Non-Metal	55 K	90 K	1.32
Sulphur	32	Yellow Color	Non – Metal	393 K	718 K	2.06
Selenium	78.96	Black, Red, and Grey Allotropes	Non – Metal	490 K	958 K	4.19
Tellurium	127.60	Silver Gray Lusture	Metalloid	725 K	1260 K	6.25
Polonium	210	Silver Coloured	Metal	520 K	1235 K	9.4

Chemical Properties of Group 16 Elements

The chemical Properties of Group 16 Elements are mentioned below:

• Oxidation Number: The oxidation number in the case of Group 16 element is -2, +4 and +6.
• Reactivity with Oxygen: Group 16 elements form oxides EO₂ and EO₃.
• Reactivity with Hydrogen: Group 16 elements form Hydride in the form of H₂E after reacting with Hydrogen.
• Reactivity with Halogen: Group 16 elements form Halide of the form EX₆, EX₄ and EX₂ where X is a halogen element.

Note that E in the above-mentioned compounds represents Group 16 Elements.

Uses of Group 16 Elements

• Steel, plastics, and textile manufacture, steel and other metal brazing, welding, and cutting, rocket propellant, oxygen therapy, and life support systems in aeroplanes, submarines, spaceflight, and diving are all frequent applications of oxygen.
• Sulphur is used as a fungicide, insecticide, and fumigant, as well as in the production of black gunpowder, matches, and fireworks. It is also used in the vulcanization of rubber and as a fungicide, insecticide, and fumigant.
• Selenium is utilised in the manufacture of ceramic, paint, and plastic pigments. It’s used in photovoltaic cells, solar cells, and photocopiers.
• Tellurium is used in rubber vulcanization, glass and ceramic tinting, solar cells, rewritable CDs and DVDs, and as an oil refining catalyst.
• Polonium has just a few applications, all of which are connected to its radioactivity: space probe heaters, antistatic devices, neutron and alpha particle producers, and poison, to name a few.

Read More

• Periodic Classification of Elements
• Alkali Metals
• d-block Elements

FAQs on Group 16 Elements

1. What are Group 16 Elements Called?

After the group’s earliest member, Group 16 is known as the oxygen family. The first four elements of this group are known as chalcogens, which means ore-forming elements, because many metal ores are oxides and sulphides.

2. What are the Atomic and Physical Properties of Group 16 Elements?

• As we move down the group-16 from oxygen to polonium, the atomic and ionic radii grow.
• As you move down the group, the ionisation enthalpies of the elements diminish.
• As the atom’s size lowers, the electron gain enthalpy drops, yet oxygen has the least negative electron gain enthalpy.
• As the atomic size increases from oxygen to tellurium, the melting and boiling points increase.
• The non-metals oxygen and sulphur are the first two elements. Metalloids include selenium and tellurium, whereas polonium might be categorised as a metal.
• The oxidation states of the elements in group 16 are 2,+2,+4, and +6.

3. What are the Uses of Group 16 Elements?

1. The usage of oxygen is required in the manufacture of steel, polymers, and textiles, as well as brazing, welding, and cutting steel and other metals.
2. Black gunpowder, matches, and pyrotechnics are all made using sulphur.
3. Selenium pigments are employed in the manufacture of ceramics, paints, and polymers. It’s used in photovoltaic cells, solar cells, and photocopiers.
4. Tellurium has been utilised in rubber vulcanization, glass and ceramic tinting, solar cells, rewritable CDs and DVDs, and as an oil refining catalyst.
5. Polonium is employed in a limited number of applications, such as space probe heaters, antistatic devices, neutron and alpha particle producers, and poison.

4. Explain the Occurrence of Group 16 Elements.

When looking at the elements in Group 16, it’s clear that oxygen is the most prevalent, accounting for 46.6 percent of the earth’s crust. The oxygen content of dry air is around 20.946 percent. Sulphur is found in volcanoes as sulphides, organic materials such as hair, mustard, and wood, and as sulphates such as gypsum, epsom, and baryte, and is found in volcanoes as sulphides, organic materials such as hair, mustard, and wood, and as sulphates such as gypsum, epsom, and baryte. Metal selenides and tellurides include selenium and tellurium, respectively, whereas polonium is a decay product of uranium and thorium.

5. What are the Chemical Properties of Group 16 Elements?

Group 16 elements have the following chemical properties:

1. Reactivity with Hydrogen: Group 16 elements generate hydrides when they react with hydrogen. H2E is the formula, and E can be O, S, Se, Te, or Po.
2. Oxygen Reactivity: These elements are for oxides of type EO3 or EO2. E can be O, S, Se, Te, or Po, as previously stated. Ozone and sulfur dioxide are gases, but selenium dioxide is a solid.
3. Halides can be generated with types EX6, EX4, and EX2 due to their halogen reactivity. E stands for a Group 16 lament, while X stands for a halogen.

6. What is Ozone?

Ozone is a gas that may be found in the high atmosphere. It’s an essential component that protects the crust from harmful UV rays. Ozone is another oxygen allotrope. Ozone is a pale blue gas in its pure state, a dark blue liquid, and a violet-black solid in its liquid state. CFCs, such as freons, aerosols, and refrigerants, pose a hazard to the ozone layer.

7. How can Dioxygen be Prepared? 

• When you heat oxygen-containing salts like nitrates, chlorates, and permanganates.
• From the thermal degradation of low-electrochemical-series metal oxides, as well as higher-electrochemical-series metal oxides.
• In the breakdown of hydrogen peroxide into water and dioxygen, catalysts such as finely split metals and magnesium dioxide are used.
• Water electrolysis

8. What is Group 16 Elements Electronic Configuration?

The General Electronic Configuration of Group 16 Elements is ns²np⁴

9. Why Group 16 Elements are called Chalcogens?

Group 16 Elements are called Chalcogens because the ores of Copper (called Chalkos in the Greek Language) have ores in the form of oxide and sulfide with traces of selenium and tellurium in them.