Group 14 Elements (Carbon Family): Properties and Reactions

Edited By Shivani Poonia | Updated on Jul 02, 2025 07:01 PM IST

Pause for a moment and just try to imagine a world where carbon was not there, an element that acts as the backbone for all kinds of organic life. From the carbon dioxide we exhale to the diamond engagement rings that speak of love, carbon surrounds us through the environment. However, carbon is just one member among the interesting elements of group 14 of the periodic table; otherwise, it is known as the carbon family. This group consists of carbon, C, silicon, Si, germanium, Ge, tin, Sn and lead, Pb. Each of these elements, in fact, has a very big impact on the different industries and applications we can have in our daily lives. For example, silicon forms the backbone of the electronics industry, including the one that gets the job done for us with our computers, smartphones, and other devices.

This Story also Contains

Physical Properties of Group 14 Elements - 1
Physical Properties of Group 14 Elements -2
Relevance and Applications of Group 14 Elements
Some Solved Examples
Summary

Group 14 Elements (Carbon Family): Properties and Reactions

Electronic Configuration
The valence shell electronic configuration of these elements is ns²np². The inner core of the electronic configuration of elements in this group also differs.

Covalent Radius
There is a considerable increase in covalent radius from C to Si, thereafter from Si to Pb a small increase in radius is observed. This is due to the presence of completely filled d and f orbitals in heavier members.

Ionization Enthalpy
The first ionization enthalpy of group 14 members is higher than the corresponding members of group 13. The influence of inner core electrons is also visible here. In general, the ionization enthalpy decreases down the group. The small decrease in $\Delta_{\mathrm{i}} \mathrm{H}$ from Si to Ge to Sn and a slight increase in $\Delta_{\mathrm{i}} \mathrm{H}$ from Sn to Pb is the consequence of poor shielding effect of intervening d and f orbitals and increase in size of the atom.

Electronegativity
Due to the small size, the elements of this group are slightly more electronegative than group 13 elements. The electronegativity values for elements from Si to Pb are almost the same.

Physical Properties of Group 14 Elements - 1

The elements of Group 14 range from non-metal to post-transition metal; this means they do show a qualitative variation in the physical properties down the group. It is because of the addition of electron shells that the atomic radius increases from carbon to lead. A small atomic radius for carbon can give strong covalent bonds, resulting in the hardest natural substance, the diamond, and also one that is soft, graphite. Silicon and germanium are metalloids. They have some of the typical properties of metals and some of the typical properties of nonmetals—moderate electrical conductivities, and they are quite thermally stable. Tin and lead are metals that show common trends, they are malleable and ductile. It conforms to the general decrease in melting and boiling points down the group, except carbon, with a much higher value as a consequence of the very strong covalent bonds within the network structures.

Allotropy
The ability of an element to exist in more than one physical form is called allotropy. All the elements of this group except Pb exhibit allotropy. Carbon has three allotropes i.e, diamond, graphite, and fullerene

Valency
All the elements of this group show tetravalency as they have 4 electrons in their valence shell.

Atomic and Ionic radii
As we move down the group, the radius of these elements increases.

Multiple Bonding
Carbon forms p_$\pi$-p_$\pi$ bonding with itself and with S, N, and O. While the other elements of this group form p_$\pi$-d_$\pi$ bonding as they have a vacant d-orbital while carbon does not have.

Physical Properties of Group 14 Elements -2

One of the interesting physical properties related to carbon is allotropy. It has a number of allotropes resulting, which include diamond, graphite, graphene, or fullerenes. All these allotropes commonly depict customary physical characteristics of carbon: diamond, for one, being very hard, depicts a good conduction of heat; graphite has lubricating and electrical-conducting properties. In fact, silicon comes in many crystalline forms, the best known being the diamond cubic structure. The bandgap of silicon makes this an extremely important factor for semiconductor devices. Germanium is also somewhat like silicon, although less abundant and not quite so versatile in its uses either. It finds applications in specialized electronic devices. The metal tin exists in two allotropes: white tin, a metallic, ductile conductor of electricity, and gray tin, a brittle, non-metallic semiconductor. Finally, lead is the densest and most metallic member of this family. It is a very malleable metal with good resistance to corrosion and, therefore, finds applications in many kinds of industries.

Hydrides

All the members of this group form covalent hydrides.
Hydrides of carbon are called hydrocarbons.
Hydrides of Si and Ge are known as silanes and germanes.
The thermal stability of hydrides decreases down the group.
Reducing character increases down the group

Relevance and Applications of Group 14 Elements

The carbon family elements play a very meaningful role in many spheres. As far as organic chemistry is concerned, carbon goes without saying that it makes the basic constituent of organic compounds and, therefore, the very backbone of life in the form of organic chemistry. Industrially, the allotropes of carbon have a magnitude of applications, from the creation of tools to lubricants and electrodes, especially because of the semiconductor property that is characteristic of silicon and which, because of its allotropic nature, makes this material the backbone of the electronics industry and of the basic components for the production of integrated circuits and solar cells.

Halides

These elements can form halides of the formula MX₂ and MX₄(where X = F, Cl, Br, I). Except carbon, all other members react directly with halogen under a suitable condition to make halides. Most of the MX₄ are covalent in nature. The central metal atom in these halides undergoes sp³hybridization and the molecule is tetrahedral in shape. Exceptions are SnF₄ and PbF₄, which are ionic in nature. PbI₄ does not exist because Pb—I bond initially formed during the reaction does not release enough energy to unpair 6s²electrons and excite one of them to a higher orbital to have four unpaired electrons around lead atom. Heavier members Ge to Pb are able to make halides of formula MX₂. The stability of dihalides increases down the group. Considering the thermal and chemical stability, GeX₄ is more stable than GeX₂, whereas PbX₂ is more stable than PbX₄. Except for CCl₄, other tetrachlorides are easily hydrolyzed by water because the central atom can accommodate the lone pair of electrons from the oxygen atom of a water molecule in d orbital.

All members when heated in oxygen form oxides. There are mainly two types of oxides, i.e., monoxide and dioxide of formula MO and MO₂ respectively. SiO only exists at high temperatures. Oxides in higher oxidation states of elements are generally more acidic than those in lower oxidation states. The dioxides — CO₂, SiO_2, and GeO₂ are acidic, whereas SnO₂and PbO₂ are amphoteric in nature. Among monoxides, CO is neutral, GeO is distinctly acidic whereas SnO and PbO are amphoteric.

Some Solved Examples

Example 1
Question: Which of the following pairs have equal electronegativity?
1) C and Si
2) Si and Ge
3) Ge and Sn
4) (2) and (3) both

Solution: The electronegativity values for Group 14 elements decrease from carbon to lead, but not in a regular manner due to the filling of d and f orbitals. The electronegativity of carbon (C) is 2.5, while silicon (Si), germanium (Ge), and tin (Sn) each have an electronegativity of 1.8. Therefore, both Si and Ge and Ge and Sn have equal electronegativity values. Hence, the correct answer is option (4).

Example 2
Question: 'X' melts at a low temperature and is a bad conductor of electricity in both liquid and solid states. X is:
1) Carbon tetrachloride
2) Silicon carbide
3) Mercury
4) Zinc sulphide

Solution: Carbon tetrachloride (CCl4) is a non-polar compound with a melting point of −22.92°C. It is a poor conductor of electricity in both liquid and solid states because it is a non-electrolyte and a covalent compound, meaning it consists of molecules with no charge separation. Hence, the correct answer is option (1).

Example 3
Question: The melting point of silicon is:
1) Higher than B
2) Lower than Al
3) Higher than C
4) Lower than C

Solution: The melting points of the elements in Group 14 vary. For example, boron (B) has a melting point of 2553 K, aluminum (Al) has a melting point of 933 K, carbon (C) has a melting point of 4373 K, and silicon (Si) has a melting point of 1693 K. From this data, we see that silicon has a lower melting point than carbon. Hence, the correct answer is option (4).

Summary

The elements of Group 14 that fall in the carbon family vary over a diverse set of variations in the physical properties down the group. From the covalent bond of carbon to allotropy, from semiconductor features of silicon and germanium to metallic properties for tin and lead, these elements would all be essential in application. Generally, it is their divergent properties that would hold a central position in aspects of electronics, material science, chemistry, and industry. Knowing the physical properties and the possibilities of usage for an element of group 14, one realizes how important and helpful they are from an academic and also practical point of view.

Frequently Asked Questions (FAQs)

1. 1. What some of the essential physical properties of carbon are?

Carbon has allotropic physical properties. In connection to this matter, a diamond is very hard and provides high thermal conductivity while graphite is very soft, slippery, and electrically conductive. Graphene is basically one atomic layer of carbon atoms known nowadays due to its strength and electrical properties.
• Application: Diamond in instruments that need sharp pointed cutting edges and as a gemstone; graphite as lubricating agents and as electrodes in cells. Graphene is planned for high-performance gadgets and materials because of its properties, which are just mind-blowing.

2. 2. Which of the physical properties of silicon qualify it to be used in electronics?

That is, the electrical conductivity of silicon is good to be modulated, meaning doped, only as required for the application in semiconductors. Its widespread usage can be attributed to the added advantage of availability along with thermal stability, hence its popular use in electronic applications—mainly microchips and solar cells.
Solution: The semiconducting properties of silicon have been put to use in making integrated circuits to power today's myriad of electronic devices. Solar cells based on silicon are a basic building block of renewable energy technology.

3. 3. What are the allotropes of tin, and how do they differ?

There are two essential allotropes of tin: white and gray tin. White tin is a metallic, conductive, and ductile form of the metal, mostly used in alloys and plating. Gray tin is the form in which it has become brittle and nonmetallic; it typically forms at low temperatures and tends to make other tins fall to pieces, a condition known as "tin pest."
Solution: White tin is used for soldering and plating other metals as a means of protecting them against corrosion. Gray tin is rather useless as it turns out to be very brittle and crumbles readily at low temperatures; thus, it needs special care in storage and handling.

4. 4. How could a deadly metal like lead ever find its uses?

It finds application in the unique properties that outweigh its toxicity. Some of the common applications include the use of lead-acid batteries in cars and standby power systems, and in radiation shielding due to its high density, where high effectiveness in blocking X-rays and gamma rays is realized. However, its use is being more and more controlled and restricted in many applications these days.
Solution: All automobile and standby power applications utilize restored lead-acid batteries because they are reliable and relatively cheap. The blocking effect of the radiation of lead is of paramount importance in protecting human health and equipment from damage in a medical or industrial environment.

5. 5. Compare Germanium's Properties to Those of Silicon

Although in most ways germanium is semiconducting like silicon, it has a larger refractive index and works better at very low temperatures; it finds special usage in very limited applications involving in the fields of fiber optics, infrared optics, and some kinds of transistors and diodes where its altered characteristics give it an edge, although compared to silicon, germanium is less common and more expensive.
• Solution: Germanium has a brilliant refractive index; thus, it is useful in high-performance fiber optic systems and improves the capabilities of data transmission. The germanium lenses find an application in infrared optics, particularly in thermal imaging cameras. Its semiconductor properties are applied to certain electronic elements where performance at really low temperatures may turn out to be crucial.

6. What is the general electronic configuration of Group 14 elements?

The general electronic configuration of Group 14 elements is ns2np2, where n represents the outermost energy level. This configuration results in four valence electrons, which play a crucial role in their chemical behavior and bonding patterns.

7. How does the atomic radius change down Group 14, and why?

The atomic radius increases down Group 14. This is because as we move down the group, the number of electron shells increases. Despite the increasing nuclear charge, the effect of electron shielding from inner shells outweighs the increased nuclear attraction, resulting in a net increase in atomic size.

8. Why does carbon form multiple allotropes while other Group 14 elements typically don't?

Carbon forms multiple allotropes (like diamond, graphite, fullerenes) due to its ability to hybridize in different ways (sp3, sp2, sp) and form strong covalent bonds. Other Group 14 elements have larger atomic sizes and weaker covalent bonding tendencies, limiting their ability to form diverse allotropes.

9. What is the reason for the existence of subshells in the heavier Group 14 elements?

Heavier Group 14 elements have subshells due to their larger atomic sizes and more complex electronic structures. These subshells (particularly d and f orbitals) can participate in bonding and affect the chemical properties of these elements, leading to phenomena like the inert pair effect and variable oxidation states.

10. Why does silicon dioxide (SiO2) have a much higher melting point than carbon dioxide (CO2)?

Silicon dioxide (SiO2) has a much higher melting point than carbon dioxide (CO2) because SiO2 forms a giant covalent network structure, while CO2 exists as discrete molecules. The extensive 3D network of strong Si-O bonds in SiO2 requires much more energy to break compared to the weak intermolecular forces between CO2 molecules.

11. Why does carbon have a much higher melting point compared to other Group 14 elements?

Carbon has a much higher melting point because it forms strong covalent bonds in its solid state (as in diamond or graphite). Other Group 14 elements have weaker metallic or covalent bonds, resulting in lower melting points. Carbon's unique bonding ability is due to its small size and high electronegativity.

12. Why are carbon and silicon considered network solids, while germanium, tin, and lead are not?

Carbon (in diamond form) and silicon are network solids because they form extended 3D structures of covalently bonded atoms. Germanium, tin, and lead have more metallic character and form crystalline structures held together by metallic bonds, not extensive covalent networks.

13. How does the metallic character of Group 14 elements change as we move down the group?

The metallic character of Group 14 elements increases as we move down the group. Carbon is a non-metal, silicon and germanium are metalloids, while tin and lead exhibit metallic properties. This trend is due to the increasing atomic size and decreasing electronegativity down the group.

14. How does the electrical conductivity of Group 14 elements change down the group?

Electrical conductivity generally increases down Group 14. Carbon (as diamond) and silicon are semiconductors, while germanium, tin, and lead are better conductors. This trend is due to the increasing metallic character and the availability of more loosely held electrons for conduction as we move down the group.

15. How does the tendency to form catenated structures change down Group 14?

The tendency to form catenated structures decreases down Group 14. Carbon shows the strongest tendency, forming millions of compounds. Silicon can form some chains, but they're less stable. Germanium, tin, and lead have very limited ability to catenate. This trend is due to increasing atomic size and decreasing bond strength down the group.

16. What is the hybridization of carbon in diamond, and how does it affect its properties?

In diamond, carbon atoms are sp3 hybridized, forming a tetrahedral structure with strong covalent bonds in all directions. This hybridization results in diamond's extreme hardness, high melting point, and electrical insulating properties.

17. Why does silicon form a stable oxide layer while carbon doesn't?

Silicon forms a stable oxide layer (SiO2) because it has a larger atomic size than carbon, allowing for the formation of a network covalent structure. Carbon, being smaller, forms discrete CO2 molecules instead. The SiO2 layer protects the underlying silicon from further oxidation.

18. What is the significance of carbon's ability to form catenated structures?

Carbon's ability to form catenated structures (chains or rings of carbon atoms) is significant because it allows for the creation of a vast number of organic compounds. This property is the basis for the entire field of organic chemistry and is essential for life as we know it.

19. How does the reactivity of Group 14 elements with oxygen change down the group?

The reactivity of Group 14 elements with oxygen generally decreases down the group. Carbon readily forms CO2, while silicon forms a protective oxide layer. Germanium, tin, and lead form oxides less readily. This trend is due to increasing metallic character and decreasing electronegativity down the group.

20. Why are Group 14 elements called the carbon family?

Group 14 elements are called the carbon family because carbon is the first and most well-known element in this group. All elements in this family share similar electronic configurations and chemical properties, with carbon serving as the representative element.

21. How does the stability of the +2 oxidation state change down Group 14?

The stability of the +2 oxidation state increases down Group 14. Carbon rarely exhibits a +2 state, while lead(II) compounds are quite stable. This trend is due to the inert pair effect, where the s electrons become more stable and less likely to participate in bonding for heavier elements.

22. How does the nature of oxides change down Group 14?

The nature of oxides changes from acidic to amphoteric to basic down Group 14. CO2 is acidic, SiO2 is weakly acidic, GeO2 is amphoteric, while SnO2 and PbO2 show increasing basic character. This trend reflects the gradual change from non-metallic to metallic character down the group.

23. What is the concept of inert pair effect, and how does it affect the chemistry of heavier Group 14 elements?

The inert pair effect refers to the reluctance of the s electrons in the outermost shell to participate in bonding for heavier elements. In Group 14, this effect becomes significant for tin and lead, causing them to sometimes exhibit a +2 oxidation state instead of +4. This effect is due to the increased stability of the s electrons in larger atoms.

24. How does the reactivity of Group 14 elements with halogens change down the group?

The reactivity of Group 14 elements with halogens generally decreases down the group. Carbon reacts vigorously with halogens, while the reaction becomes less exothermic for heavier elements. This trend is due to increasing atomic size and decreasing electronegativity, which results in weaker bonds with halogens.

25. What is the trend in electronegativity down Group 14, and how does it affect the elements' reactivity?

Electronegativity decreases down Group 14. Carbon is the most electronegative, while lead is the least. This trend affects reactivity by influencing the elements' ability to form covalent bonds and their tendency to gain or lose electrons. Higher electronegativity (as in carbon) leads to stronger covalent bonding and more non-metallic behavior.

26. Why does carbon form strong π bonds while heavier Group 14 elements typically don't?

Carbon forms strong π bonds due to its small atomic size, which allows for effective orbital overlap. Heavier Group 14 elements have larger atomic sizes, resulting in less effective orbital overlap and weaker π bonds. This is why carbon can form stable double and triple bonds, while such bonds are rare or unstable for heavier elements.

27. How does the boiling point trend of Group 14 hydrides (CH4, SiH4, GeH4, SnH4, PbH4) differ from the general trend in the group, and why?

The boiling point trend of Group 14 hydrides is anomalous: CH4 < SiH4 < GeH4 > SnH4 > PbH4. This differs from the general increasing trend down the group. The anomaly is due to the increasing importance of van der Waals forces for SiH4 and GeH4, while for SnH4 and PbH4, the molecules become so large that these forces decrease in effectiveness.

28. What is the significance of carbon's ability to form sp, sp2, and sp3 hybridized orbitals?

Carbon's ability to form sp, sp2, and sp3 hybridized orbitals is significant because it allows carbon to form a wide variety of molecular structures. This versatility enables carbon to create single, double, and triple bonds, as well as form different geometric shapes (linear, trigonal planar, tetrahedral). This is the basis for the vast diversity of organic compounds.

29. How does the stability of the +4 oxidation state change down Group 14?

The stability of the +4 oxidation state generally decreases down Group 14. Carbon and silicon readily form +4 compounds, while for germanium, tin, and especially lead, the +2 state becomes increasingly stable. This trend is due to the inert pair effect, where the s electrons become less likely to participate in bonding for heavier elements.

30. Why does carbon form strong covalent bonds while lead tends to form more ionic bonds?

Carbon forms strong covalent bonds due to its high electronegativity and small atomic size, which allow for effective orbital overlap. Lead, being larger and less electronegative, has a greater tendency to lose electrons and form ionic bonds. This shift from covalent to more ionic bonding is part of the general trend of increasing metallic character down Group 14.

31. How does the reactivity of Group 14 elements with water change down the group?

The reactivity of Group 14 elements with water generally increases down the group, but in a complex way. Carbon is unreactive with water. Silicon reacts slowly to form silicic acid. Germanium is more reactive, while tin and lead react to form hydroxides. This trend is influenced by the increasing metallic character and the ability to form stable oxides or hydroxides.

32. What is the trend in first ionization energy down Group 14, and why does this trend occur?

The first ionization energy generally decreases down Group 14. This trend occurs because as the atomic size increases, the valence electrons are farther from the nucleus and experience more shielding from inner electrons. Consequently, less energy is required to remove the outermost electron from atoms of heavier elements in the group.

33. How does the ability to form organometallic compounds change down Group 14?

The ability to form organometallic compounds increases down Group 14. While carbon forms purely organic compounds, silicon, germanium, tin, and lead can form organometallic compounds with increasing stability. This trend is due to the increasing metallic character and the ability of heavier elements to expand their octet and form more diverse bonding arrangements.

34. Why does carbon dioxide behave differently from the dioxides of other Group 14 elements?

Carbon dioxide (CO2) behaves differently from other Group 14 dioxides because it forms discrete linear molecules, while others (like SiO2) form network structures. CO2 is a gas at room temperature and doesn't react with water to form an acid. This difference is due to carbon's smaller size and stronger covalent bonding, which favors the formation of double bonds over extended networks.

35. How does the tendency to form complexes change down Group 14?

The tendency to form complexes increases down Group 14. Carbon rarely forms complexes, while silicon, germanium, tin, and lead show an increasing ability to form complex ions and coordination compounds. This trend is due to the increasing availability of empty d orbitals for bonding and the elements' growing metallic character down the group.

36. What is the trend in the reducing power of Group 14 elements, and how does it relate to their standard electrode potentials?

The reducing power of Group 14 elements generally increases down the group. Carbon is a poor reducer, while lead is a stronger reducing agent. This trend correlates with the standard electrode potentials becoming more negative down the group. The increasing reducing power is due to the elements' growing tendency to lose electrons as their metallic character increases.

37. Why does silicon form silicates while carbon doesn't form analogous carbonates in the same way?

Silicon forms silicates because it can expand its octet and form stable Si-O-Si bridges in three-dimensional networks. Carbon, being smaller and having a fully filled valence shell, cannot expand its octet. Instead of forming network structures, carbon in carbonates is bonded to oxygen in a planar arrangement, resulting in discrete carbonate ions.

38. How does the stability of hydrides change down Group 14?

The stability of hydrides decreases down Group 14. Methane (CH4) is very stable, while plumbane (PbH4) is highly unstable and decomposes readily. This trend is due to the decreasing strength of the element-hydrogen bond as the atomic size of the Group 14 element increases, making the hydrides of heavier elements more prone to decomposition.

39. What is the significance of the "tetrel bond" in Group 14 chemistry?

The "tetrel bond" is a type of non-covalent interaction involving Group 14 elements. It's significant because it plays a role in molecular recognition, crystal engineering, and biochemical processes. Tetrel bonds are weaker than typical covalent bonds but can influence the properties and behavior of molecules containing Group 14 elements.

40. How does the tendency to form intercalation compounds change down Group 14?

The tendency to form intercalation compounds generally increases down Group 14. Carbon (as graphite) can form intercalation compounds, and this ability becomes more pronounced for silicon and germanium. This trend is related to the increasing metallic character and the ability of heavier elements to accommodate guest species between layers of their structures.

41. Why does carbon form fullerenes while other Group 14 elements typically don't?

Carbon forms fullerenes due to its unique ability to form stable, curved structures through sp2 hybridization and delocalized π-bonding. Other Group 14 elements have larger atomic sizes and prefer to form extended network structures or simple molecular compounds, making it energetically unfavorable for them to adopt the highly curved structures characteristic of fullerenes.

42. How does the reactivity with acids change down Group 14?

The reactivity with acids generally increases down Group 14. Carbon is mostly unreactive with acids, silicon reacts only with HF, while germanium, tin, and lead show increasing reactivity with various acids. This trend is due to the increasing metallic character and the greater ease of losing electrons for heavier elements in the group.

43. What is the trend in the covalent radius down Group 14, and how does it affect bonding?

The covalent radius increases down Group 14 due to the addition of electron shells. This increase affects bonding by generally leading to longer, weaker bonds for heavier elements. It also contributes to the decreasing tendency to form multiple bonds and the increasing metallic character observed down the group.

44. How does the ability to form alloys change down Group 14?

The ability to form alloys increases down Group 14. Carbon forms few alloys, while tin and lead readily form alloys with many metals. This trend is due to the increasing metallic character down the group, which allows for easier mixing with other metals in various proportions.

45. Why does the melting point trend in Group 14 show an anomaly?

The melting point trend in Group 14 shows an anomaly: C > Si > Ge > Sn > Pb, with carbon having an exceptionally high melting point. This anomaly is due to carbon's unique ability to form strong covalent network structures (as in diamond) or extensive layer structures (as in graphite), requiring much more energy to break compared to the metallic or weak covalent bonds in heavier elements.

46. How does the tendency to form halides change down Group 14?

The tendency to form halides increases down Group 14, with a shift from covalent to more ionic character. Carbon forms covalent halides, while lead halides are more ionic. The stability of higher oxidation state halides (e.g., MCl4) decreases down the group, while lower oxidation state halides (e.g., MCl2) become more stable for heavier elements.

47. What is the significance of the "inert s-pair" in the chemistry of heavier Group 14 elements?

The "inert s-pair" refers to the ns2 electrons in heavier Group 14