Group 14 Chemistry

Notes Group 14 Chemistry

Chen

Chong

Fam

Lim

Mook

Ng

Tew

Wong

 

Related Articles 11 Group 14

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group 14 elements picture real

– List out elements in group 14.

C, carbon

Si, silicon

Ge, germanium

Sn, tin

Pb, lead

group 14 elements carbon silicon germanium tin lead electronic configuration atomic number

– What is the type of bond that is related to group 14 elements’ melting points?

Group 14 consists of carbon, silicon, germanium, tin, and lead. Carbon is a non-metal, silicon and germanium are metalloids, and tin and lead are metals. With 4 valence shell electrons, elements of the carbon family tend to form covalent compounds. With increasing mass and atomic radius these elements become increasingly metallic and have lower melting and boiling points.

 

– Electrical conductivity of elements in group 14. Give reasons why it is conductor, semiconductor, or insulator?

Change in electrical conductivity when going down group 14 – INCREASES.

Going down group 14, the increasing atomic radius causes the valence electrons to become more delocalised. The properties of the elements change from non-metallic to metallic. The metallic character increases. As a result, the electrical conductivity increases.

 

C =

C, conduct (graphite) – good conductor due to the mobility of the electrons in its outer valence shells.

– Each carbon atom forms three covalent bonds with other carbon atoms.

– The carbon atoms form layers of hexagonal rings.

– There are no covalent bonds between the layers.

– There is one non-bonded (or delocalised) electron from each atom.

– Can conduct electricity.

 

C, insulator (diamond) – there are no delocalised electrons in the giant covalent structure.

– Each carbon atom is joined to four other carbon atoms by strong covalent bonds.

– The carbon atoms form a regular tetrahedral network structure.

– There are no free electrons.

– Does not conduct electricity.

 

Si, Silicon = Semiconductor – metalloids / semi metal.

Ge, Germanium = Semiconductor – metalloids / semi metal.

Sn, Tin = Good conductor – They have delocalised electrons in their giant metallic structures.

Pb, Lead = Good conductor – They have delocalised electrons in their giant metallic structures.

 

– What are the key differences between simple covalent molecules and giant covalent structures?

As a result, simple covalent substances generally have low melting/ boiling points. Giant covalent substances, such as diamond, contain many strong covalent bonds in a 3D lattice structure. Between each carbon atom in diamond, there are 4 strong covalent bonds.

 

– Why Carbon has more electrical conductivity than Silicone? [conduct = valence electrons can move freely]

Carbon has greater electrical conductivity compared to Silicone. As although C is a non-metal it contains more delocalised electrons and is considered a good electrical conductor while Si is a metalloid which is a semiconductor. sp2 hybridised in carbon atom, each C atom has one free p orbital, overlaps p orbitals forms a p electron cloud above and below the plane (sheet) of carbon atoms enables free valence electrons to be delocalised over the entire graphite crystal.

Graphite = electrically conducted because electrons is able to move freely when electrical fields is applied.

 

– When down to group 14, what happens to their melting point? (From carbon to stanum is decrease and slightly increase from Sn to plumbum) and why is it so?

The melting point of group 14 when down to group is decreases, then increases. When down to group 14, the size of atom is increasing. The attractive force between the atom will decrease.

Group 14 consists of carbon, silicon, germanium, tin, and lead. Carbon is a non-metal, silicon and germanium are metalloids, and tin and lead are metals. With 4 valence shell electrons, elements of the carbon family tend to form covalent compounds. With increasing mass and atomic radius these elements become increasingly metallic and have lower melting and boiling points.

 

– How to explain melting point in group 14?

Group 14 (carbon family) elements have much higher melting points and boiling points than the group 13 elements. Melting and boiling points in the carbon family tend to decrease moving down the group, mainly because atomic forces within the larger molecules are not as strong.

 

– Which element has the highest melting point in the periodic table?

Carbon. 

 

– What is Carbon’s (diamond) melting point and boiling point?

Carbon (diamond). 

melting point = 3,550 °C (6,420 °F). 

boiling point = 4,827 °C (8,721 °F)

 

– Which element has the lowest melting point in the group 14?

Stanum.

 

– Carbon can form 4 covalent bonds each atom, same goes to silicon, then why does silicon have a lower melting point? Why does carbon have a higher melting point than silicon?

Silicon like Carbon has covalent bonding as it is group 4 like Carbon. Also The Bond length between CarbonCarbon atoms is lesser than that of Silicon making it harder to break the bonds. Hence Carbon has much higher melting point than that of Silicon.

 

– Why does carbon have a higher melting point than Sn (tin)?

C has a smaller atomic radius, so C has stronger covalent bonds, more energy is required to break the bonds between atoms of C (giant covalent structure). Carbon atoms held together by strong covalent bonds in a giant covalent network.

Sn has larger atomic radius than C. Sn is a metal and due to its larger atomic size, in this cases, its metallic bond is relatively weak because it has larger size (atomic radius). This causes less heat energy to break the bonds. Thus, C has a higher melting point compared to Sn.

 

– Allotropes of carbon?

graphite graphene carbon nanotube fullerene diamond

Graphite, graphene, carbon nanotube, fullerene and diamond

Diamond, graphite and fullerenes.

– Drawing the structures shows the difference of diamond and graphite?

Graphite (sp2 hybridized carbon atom) has a planar (sheet/ kepingan) structure while diamond (sp3 hybridised carbon atom) has a face-centered cubic crystal structure in 3D arrangement network.

 

– Why do allotropes of carbon have high melting points?

They have strong covalent bonds between atoms (smaller atomic size) in a giant covalent structures/ networks. Hence, more energy is required to break the covalent bonds. As a result, they have high melting points.

 

– Compare diamond and graphite in terms of structures bonding, electrical conductivity and hardness?

Diamonds:

sp3 orbitals arranged in a tetrahedral.

Insulator, because of all the valence electrons used in bonding.

The hardest substances is because of the 3D network of strong single covalent bonds.

Graphite:

sp2 hybridised arranged in a plane (sheet).

Conductor, because the delocalised p electrons can move between the planes of the carbon atoms (use as an electrode).

The soft, slippery is because of the sheet – like structure the layers held together by weak London dispersions forces.

allotropes of carbon graphite and diamond

– Tetrachloride of group 14, CCl4, SiCl4, GeCl4, SnCl4 and PbCl2. What is the thermal stability when down group 14?

Thermal stability when down group 14 decreases.

CCl4 – liquids at room temperature and pressures.

SiCl4 – liquids at room temperature and pressures.

GeCl4 – liquids at room temperature and pressures.

SnCl4 – liquids at room temperature and pressures.

PbCl2 – liquids at room temperature and pressures.

 

– Which one has highest melting point? CH4, SiCl4, SnCl2, SnCl4, PbCl4

SnCl2 has the highest melting point.

CH4 – weak van der Waals forces.

SiCl4 – weak van der Waals forces.

SnCl2 – ionic compounds, ions held together by strong ionic bonds.

SnCl4 – weak van der Waals forces.

PbCl4 – weak van der Waals forces.

 

Which one has higher melting point? SiCl4, SnCl2. Give the reasons.

SnCl2 has the higher melting point.

SnCl2 – ionic compounds, ions held together by strong ionic bonds.

SnCl4 – weak van der Waals forces.

 

– Give reason for each of the following: SnCl2 ​ is a solid while SnCl4 ​ is a liquid at room temperature.

The size of Sn2+ ion is larger than Sn4+ ion. SnCl2 ​ is an ionic compound and SnCl4 ​ is a covalent compound. SnCl4 exist as a liquid because molecule are held together by weak van der Waals forces. SnCl2 ​ is solid because molecule are held with the help of strong electronic forces between the opposite charges ion.

 

– What is inert pair effect explain with example?

The inert pair effect is defined as the tendency of electrons in the outermost atomic s orbital to remain unionized in compounds of post-transition metals. For simplicity, let’s summarize it as the tendency of heavier atoms to form ions with a difference in charge of two.

inert pair effect

inert pair effect is defined

Inert pair effect is the phenomenone of electrons remaining paired in valene shell.

 

– What is the reason for inert pair effect?

Inert pair effect is mostly shown by the 15-17th group elements. That is, the oxidation state reduces by 2 for elements below (As, Sb), which is more stable than the other oxidation states. The reason for this is the inertness of the inner s electrons due to poor shielding.

 

– Why does inert pair effect increase down the group?

Since inert pair effect refers to the tendency of outermost electrons to remain unionized, the stability of the oxidation state of the elements down a particular group increases.

– What is the best way to prepare CCl4?

Heat carbon in a flow of dry Cl2 gas.

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