Question

Indicate the nature of bonding in ${\mathrm{CCl}}_4$ and ${\mathrm{CaH}}_2$.

Answer 1

Covalent bond:-

• A covalent bond is a type of bond which is formed by equal sharing of electrons from both the participating atoms.
• The pair of electrons that are participating in this bonding is called shared pair or bonding pair.
• Covalent bonds are also called as molecular bonds.
• Sharing the electrons in this bond will ensure that the atoms achieve stability obtaining the octet state which is similar to that of noble gases.
• Examples are Carbon tetrachloride ${\mathrm{CCl}}_4$, Ammonia ${\mathrm{NH}}_3$

Ionic bond:-

• It is a type of bond which is formed between two atoms by the complete transfer of one or more electrons from one atom to the other atom.
• Due to this the atoms attain their nearest inert gas configuration, obtaining octet state.
• Ionic bonds are called as electrovalent bonds.
• Examples are Calcium hydride ${\mathrm{CaH}}_2$, Sodium chloirde $\mathrm{NaCl}$

Nature of binding in ${\mathrm{CCl}}_4$:-

• Electronic configuration of Carbon is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^2$, and we can see it has 4 electrons in its outermost shell.
• Thus it neither can donate nor gain 4 electrons to obtain the nearest noble gas configuration as it would require a lot of energy to do so.
• Electronic configuration of Chlorine is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^5$, and we can see it has 7 electrons in its outermost shell.
• Thus it requires 1 electron to obtain its nearest noble gas configuration.
• Therefore,carbon shares its 4 electrons with 4 chlorine atoms to form the compound ${\mathrm{CCl}}_4$(Carbon tetrachloride).
• In this manner, both carbon and chlorine obtain their nearest noble gas configuration.

Nature of binding in ${\mathrm{CaH}}_2$:-

• The electronic configuration of calcium is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^2$, and we can see it has 2 electrons in its outermost shell.
• Thus it can donate these two electrons and hence obtain the octet state.
• On the other hand electronic configuration if hydrogen is $1{\mathrm{s}}^1$and it has only electron.
• Thus it needs 1 more electron to attain the duplet state and become stable.
• Therefore, the Calcium atom donates its two electrons to two Hydrogen atoms and thus forms the compound Calcium hydride ${\mathrm{CaH}}_2$.
• In this manner, both Calcium and Hydrogen obtain their nearest noble gas configuration.

Therefore, the nature of bonding in ${\mathrm{CCl}}_4$is covalent bonding and in ${\mathrm{CaH}}_2$ is ionic bonding.