What are group 14 elements?

Group 14 element refers to the p-block, 2nd group elements. They are also commonly called Carbon group elements. The general configuration of these elements is ns²np². The carbon family is the most abundant element group.

The following elements come under group 14 of the periodic table.

• Carbon
• Silicon
• Germanium
• Tin
• Lead

The atomic number of carbon(C) is 6, Silicon(Si) is 14, Germanium(Ge) is 32, Tin(Sn) is 50, and Lead(Pb) is 82. The valency of all these elements will be the same, that is, 4. It means these elements have 4 electrons in their outermost orbit.

Since the general configuration of these elements is ns²np², the electronic configuration of these elements will be as follows.

$$\begin{gathered} \text{Carbon (C)} - 2s^{2}2p^2 \\ \text{Silicon (Si)} - 3s^{2}3p^2 \\ \text{Germanium (Ge)} -3d^{10}4s^{2}4p^2 \\ \text{Tin (Sn)} - 4d^{10}5s^{2}5p^2 \\ \text{Lead (Pb}) - 4f^{14}5d{10}^{6}s{2}^6{p}^2 \end{gathered}$$

Properties of group 14 elements

Covalent radius

The covalent radius increases from C to Si, thereafter from Si to Pb, the radius increases a bit. It is due to filled d and f orbitals in heavier members.

Melting and boiling Points

The melting and boiling points in the group 14 elements tend to decrease down the group. It is due to weaker atomic forces within larger molecules. The melting and boiling point of carbon, silicon, and germanium is very high. The melting and boiling points of tin and lead are lower than that of carbon, silicon, and germanium.

Density

The density of group 14 elements increases with an increase in atomic number. Due to the increase in atomic number, the number of protons and electrons increases, the atomic radii also increase thus, volume and density also increase. Hence, the density of lead will be much more than that of carbon.

Ionization enthalpy

Ionization enthalpy is represented by ∆_iH. ∆_iH decreases down the group but not regularly. A decrease in ∆_iH from Si to Ge to Sn and an increase in ∆_iH from Sn to Pb is due to the poor shielding effect of intervening d and f orbitals along with an increase in the size of the atom.

Electronegativity

Because of the small size, the elements of this group are more electronegative than group 13 elements. The electronegativity of elements from Si to Pb is almost the same.

Oxidation state

They exhibit a +2 and the +4 oxidation state. Pb compounds in the +4 oxidation state are powerful oxidizing agents since the +2 oxidation state of Pb is more stable due to the inert pair effect.

The compounds in the +2 oxidation state are ionic and in the +4 oxidation state are covalent (According to Fajans' rule).

Reactivity towards water

Carbon, silicon, and germanium are not affected by water. Tin decomposes steam to form dioxide and dihydrogen gas. Lead is unaffected by water, probably because of a protective oxide film formation.

Reactivity towards halogen

Halides: All the elements give tetrahedral and covalent halides of the type MX₄ except PbBr₄ and PbI₄.

The carbon family element- carbon (C)

The carbon family belongs to the periodic table’s group 14. C, Si, Ge, tin, and Pb are the five elements in the carbon family. Flerovium,114, is likely to behave in some ways like a member of the family as well.

In other words, the group consists of carbon and the elements directly below it in the periodic table. The carbon family belongs to the p-block of elements and is almost in the center of the periodic table, with nonmetals to its right and metals to its left.

Carbon with atomic number 6 has electronic configurations $2s^{2}2p^2$shows non-metallic properties. They can form covalent as well as ionic bonds. They form covalent bonds with non-metals and ionic bonds with metals. They can also bond with themselves multiple times. A carbon atom has 6 electrons, 6 protons, and 6 neutrons.

Carbon has several forms but two forms are widely known, Diamond and graphite. They differ in their physical properties but they both have a crystalline structure. Graphite and diamond are naturally occurring substances but they can also be prepared manually or artificially.

Catenation

Catenation is the ability of an element to form long chains or ring structures by linking its atoms with one another through covalent bonds. Down the group, the catenation tendency decreases. The variation in catenation from carbon to lead follows the same order.

Anomalous behavior of carbon

Carbon is the first element of the group, differs from the rest of its group in several properties, and thus shows an anomalous behavior. This behavior of carbon may be due to the following factors, which are as follows:

1. Its small atomic size.
2. Its higher electronegativity.
3. The absence of vacant d-orbitals in its valence shell.
4. Its strong catenation tendency.

The important properties in which carbon differs from the other elements of the group are as follows:

1. Carbon is much harder than the other elements of the group. Diamond, an allotrope of carbon, is the hardest substance known.
2. The melting and boiling points of carbon are much higher as compared to those of other elements of the group.

Behavior of carbon

Carbon differs from all the elements in the group 14 category of elements because of its small size, and high electronegativity. The melting and boiling points, ionization energy, and electronegativity of carbon are very high compared to other member elements of the group.

CO₂ is a gas while the dioxide of other elements of this group are solids.

Allotropes of carbon

Allotropes of carbon can be divided into three categories.

• Natural crystalline– diamond and graphite are a type of natural crystalline allotropes of carbon.
• Artificial crystalline
• Amorphous– wood charcoal, sugar charcoal, lamp black, etc.

Other elements of the carbon family

Silicon (Si)

Silicon is an element having atomic number 14 and atomic weight 28.086. It has 14 electrons and 14 protons in it. It is hard to touch and crystalline. Silicon is a very important material as it is widely used to make alloys of other materials and also for other uses such as in making transformer plates and transistors. They are also used in making many semiconductor materials. Silicon is the second most abundant element present on earth.

Silicon has the same crystalline structure as diamond, which is an alloy of carbon, and because of this, they have luster in them.

Germanium (Ge)

Germanium has an atomic number 32 and an atomic weight of 72.631. It has 32 electrons and 32 protons. It is hard, brittle, and has a crystalline structure. Germanium is also widely used in semiconductor devices. It is also used as a catalyst in many chemical reactions.

Scientists are studying Germanium extensively for its use in chemotherapy for treating cancer. Germanium can effectively kill bacteria from our surroundings without causing any harm to humans or animals. Germanium is a metalloid having properties of both metals and non-metals.

Tin (Sn)

Tin has an atomic number 50 and its name is Stannum. Therefore it is abbreviated as Sn. It has 50 electrons and 50 protons. Its atomic weight is 118.71 and it is also crystalline. In ancient times, it was called bronze. it is silvery in color and is widely used in making food containers, cans, etc.

Since Tin is expensive, aluminum is used in place of tin for cost-cutting. it is a ductile, malleable, and non-toxic material. Tin plating helps in preventing materials from corrosion.

Lead (Pb)

Lead is an element with atomic number 82 and atomic weight 207.2. It is called Plumbum. It has a very high density and is a heavy metal.

Some important compounds of p-block

Silicon dioxide SiO₂

Silicon dioxide SiO₂ compound, also called Silica is a 3-D network structure wherein each silicon is bonded with 4 oxygen atoms which are tetrahedrally disposed around silicon. Silicon dioxide is non-reactive because of the very high Si-O bond enthalpy. SiO₂ compound is used as a piezoelectric material. It has made it possible to develop extremely
accurate clocks, TVs, and radios.

Silicates

The basic building unit of all silicate compounds is $\mathrm{Si}{O_2}^{4-}$ ion.

Silicons

These are organosilicon polymeric compounds having Si-O-Si linkage. These are used in waterproofing, lubricants, etc.

Context and Applications

This topic is useful for students who are studying in either of the following courses:

• Bachelors in Science in Chemistry
• Bachelors in Technology in Chemical Engineering

Practice Problems

1. Which of the following statements is true for group 14 elements of the periodic table?

1. Group 14 elements form metallic hydrides.
2. Group 14 elements form covalent hydrides.
3. Group 14 elements form both covalent and metallic hydrides.
4. Group 14 elements do not form hydrides.

Answer: Option b

Explanation: Group 14 elements form covalent hydrides.

2. Which of the following element does not belong to the group 14 family of the periodic table?

1. Lead (Pb
2. Germanium (Ge)
3. Nitrogen (N)
4. Carbon (C)

Answer: Option c

Explanation: Nitrogen does not belong to the group 14 elements family of the periodic table.

3. What is the atomic mass of Plumbum?

1. 205.2
2. 206.2
3. 207.2
4. 208.2

Answer: Option c

Explanation: Plumbum is the other name for lead. Its atomic mass is 207.2.

4. What is the number of neutrons in a carbon atom?

1. 6
2. 7
3. 8
4. All of the above

Answer: Option d

Explanation: A carbon atom has 6 neutrons. Isotopes of carbon have 7 or 8 neutrons.

5. Which of the following element from the carbon family is a metalloid?

1. Silicon
2. Germanium
3. Tin
4. Lead

Answer: Option b

Explanation: The elements that have properties between metals and non-metals are called metalloids or semi-metals. Germanium is an element in the carbon family which is a metalloid.

Related Concepts

• s-block elements
• p-block elements
• d-block elements
• f-block elements
• Alkane
• Alkene
• Periodic table
• Metals and non-metals
• Valency
• Semimetals and metalloid