By giving example of an Ionic compound show that its ions do not obey the octet rule.

Lithium fluoride is an ionic compound whose ions does not obey octet rule. Lithium has one valence electron and fluorine has seven valence electrons. Lithium transfers it one valence electron to fluorine and thus becomes electron deficient.

Why the bond in sodium chloride cannot be expressed as Na - Cl ?

Sodium chloride consists of ionic bonds between sodium and chlorine bonds. Each Na + ion in a sodium crystal is surrounded by six Cl – ions, and vice versa. It's impossible to tell which Na + ion belongs to which Cl – ion, or which Cl – ion belongs to which Na + ion. As a result, as a formula unit, we use a mixture of Na + and Cl – . As a result, ionic compounds like NaCl exist in the crystal lattice as aggregates of a large number of oppositely charged ions rather than as discrete molecules.

Write with an example, how according to Lewis concept, a covalent bond is formed.

The elements share electrons equally in covalent bonding, i.e. both atoms have an equal distribution of electrons in the bond. A covalent bond is formed as a result of the sharing of electrons. The bond is formed by two atomic orbitals overlapping. For the purposes of satisfying the octet rule, each shared electron will be counted towards both atoms' valence shells. Cl 2 has a covalent bond as well. The two chlorine atoms are attracted to the same pair of electrons in the chlorine molecule. In the third energy level, each chlorine atom has seven valence electrons and requires one more electron to form an electron core with an argon electron configuration. The bound pair shared by the two atoms receives one electron from each chlorine atom. Each chlorine atom's remaining six valence electrons are not involved in bonding. Non-bonding electrons, lone pair electrons, and unshared electron pairs are all terms used to describe them.

What type of chemical bond is present in CaO ?

An ionic bond is present in CaO . The atomic number of calcium and oxygen are 2 , 8 , 8 , 2 and 2 , 6 respectively. The two valence electrons of calcium transfer themselves to the oxygen atom. Hence, the Ca 2 + and O 2 - ions are held by a strong electrostatic force forming an ionic bond.

Give one example each of a liquid and a solid covalent bond.

Covalent compounds are those in which the atoms are chemically linked together by the sharing of electrons. A covalent compound can exist in three states: solid, liquid, and gaseous. Silica, for example is a covalent molecule that occurs in a solid state. Water is also a covalent molecule that occurs as a liquid. The intermolecular forces of attraction between the molecules of covalent compounds are weak. They are brittle as a result, and can be readily broken down as a result.