The Carbon Family

The Carbon family is located on the right side of the periodic table. Carbon (C), germanium (Ge), silicon (Si), lead (Pb), tin (Sn), and flerovium (Fl) belonging to Group 14 are members of the carbon family. These elements are found in the p-block of the periodic table. Thus, their electronic configuration is ns2np2. 

Carbon Family Elements

• Carbon: Carbon is the first element in the 14th periodic table group. It is abundantly available on our planet. It exists in both combined and free states. It is commonly found in air, carbonates, organic molecules, polymers, and other materials. Carbon has three isotopes: C12, C13, and C14. C14 is radioactive
• Silicon: Silicon is a metalloid and is found in various materials such as stone, dust, clay, sand, silica, and silicate minerals. Pure silicon is rarely found
• Germanium: Germanium is a rare element that is used in manufacturing semiconductor devices. Pure germanium has excellent semiconductivity. As germanium is highly reactive, it is not found in pure form and is available in traces.
• Tin: Tin is a malleable and soft metal with a low melting point. It is obtained from Cassiterite. Tin has two primary allotropes at room temperature
• Lead: Lead is extracted from a natural mineral called Galena. Lead or plumbate is used to make lead-acid batteries, alloys, and oxidising agents; however, it is toxic for humans
• Flerovium: Flerovium is a heavy artificial chemical element. It is a radioactive synthetic element

Electronic Configuration of the Carbon Family

The electronic configuration of an atom is described as the electron configuration distributed throughout the subshells and orbitals. The physical and chemical properties of the elements can be deduced from the electron configuration. The number of valence electrons in the outermost shells can be used to determine the chemistry of the elements.

Pauli’s exclusion principle, Hund’s maximum multiplicity rule, and the Aufbau principle

help in assigning electrons to orbitals to understand the electrical arrangement of elements.

Electrons fill the orbitals where the atom’s energy is lowest. Thus, according to the Aufbau principle, an element’s electrons fill the energy levels in increasing order. Pauli defined a set of unique quantum numbers for each electron. The Pauli exclusion principle asserts that two electrons in an atom cannot have the same four quantum numbers.

According to Hund’s rule, electron pairing in an orbital occurs when all subshells have one electron each. These group 14 elements have an ns2np2 electronic configuration. The outermost p orbitals of these elements have two electrons. 

Since all of the elements in group 14 have four electrons in their outermost shell, their valency is four. To achieve an octet configuration, they use these electrons in bond formation.

Oxidation States of Carbon Family Elements

The oxidation states of the group 14 elements are often +4 and +2. The tendency to build +2 ions increases as we move downward in the group due to the inert pair effect. p-block elements reveal this effect. The inert pair effect occurs when the s-orbital does not bond because the intervening electrons are poorly shielded.

The d orbital and f orbital of elements such as Sn and Pb are filled by electrons. The nuclear charge attracts the s orbital nearer to the nucleus due to the d and f orbitals low shielding ability. Thus, the s orbital is reluctant to bond formation, leaving just the p electrons to bond. Therefore, Pb4+ is an excellent oxidising agent.

Anomalous Behaviour of Carbon

The properties of carbon differ from the other members of the group due to its small atomic size, lack of d-orbital in the valence shell, high electronegativity, and high ionisation enthalpy.

 Chemical properties

1) Covalent radius

The atomic radii of group 13 elements is more than that of group 14 elements due to the increase in the effective nuclear charge. A decreased radii may be observed due to increase in effective nuclear charge. This is mostly attributed to insufficient shielding of the d and f orbitals. 

2) Ionisation enthalpy

Group 13 elements have lower ionisation energy than that of group 13 due to the difference in size. As the electrons are distant from the nucleus, the ionisation enthalpy lowers. Pb has a higher ionisation enthalpy than Sn due to the ineffective shielding of the d and f orbitals.

Physical properties

1) Melting and boiling points

Carbon, germanium and silicon have extremely high melting points. Tin and lead have a lower melting point as they form only two bonds. This is called the inert pair effect. The melting point decreases with an increase in the atomic radii as the M-M interaction decreases.

2) Metallic character

Group 14 elements are more electronegative than group 13. The metallic character becomes stronger as you progress through the group. This is due to smaller size and higher ionisation enthalpy.

3) Four covalent compounds:

This feature is present in most group 14 elements due to the presence of 4 electrons in the valence shell of the respective elements.

Conclusion

There are 6 chemical elements in the Carbon Family or Group 14 of the periodic table. These include carbon, silicon, germanium, tin, lead, and flerovium. All these elements, except carbon, reveal similar physical and chemical properties.