Question

Elements forming ionic compounds attain noble gas configuration by either gaining or losing electrons from their outermost shells. Give reason to explain why carbon cannot attain noble gas configuration in this manner to form its compounds. Name the type of bonds formed in ionic compounds and in the compounds formed by carbon. Also give reason why carbon compounds are generally poor conductors of electricity.

Answer 1

The atomic number of carbon is 6. This means that it has 4 electrons in its outermost shell and it needs 4 more electrons to attain noble gas electronic configuration. It cannot form C4+ cation, as the removal of 4 valence electrons requires a huge amount of energy. The cation formed has 6 protons and 2 electrons. This makes it highly unstable. Carbon cannot form C4− anion, as its nucleus with 6 protons cannot hold 10 electrons. Thus, carbon achieves noble gas electronic configuration by sharing its 4 electrons with other elements—that is, it forms covalent compounds. In ionic compounds, ionic bonds are formed; while in carbon compounds, covalent bonds are formed. Because carbon compounds are covalent in nature, they are bad conductors of electricity; they lack free electrons.

Answer 2

Answer:

i. Carbon has 4 electrons in its outermost shell. It

cannot lose 4 electrons to form C4+ because very

high energy is required to remove 4 electrons.

ii It cannot gain 4 electrons to form C4– ions

because it is difficult for 6 protons to hold on to

10 electrons.

iii Ionic/Electrovalent bonds in ionic compounds;

and Covalent bonds in the compounds formed

by carbon.

iv There are no charged particles in carbon

compounds and hence they are poor conductors

of electricity.