Write three necessary conditions for the formation of covalent book
Answers
Sorry I know only 2 of them :-
(ii) A high difference of electro negativity of the two atoms is necessary for the formation of an electrovalent bond. The Electrovalent bond is not possible between the similar atoms.
(iii) There must be overall decrease in energy which means that the energy must be released.
Explanation:
Valence electrons
(A) The conditions required for the formation of covalent bond are :
1. The atoms having no tendency to lose electrons form covalent bonds
2. The two combining atoms should have equal attraction for electrons.
3. Each of the two combing atoms should have 5, 6 or 7 electrons in their valence shells or the outermost shells. In such cases, both the atoms achieve the stable octet by sharing 3,2 or 1 electron pair respectively. The nonmetals of groups VA, VIA and VIIA respectively satisfy this condition and hence they are capable of covalent-bond formation.
4. Covalent bond is favoured most when the combining atoms come from the electronegative elements. Thus, electronegative element + electronegative element—covalent bonding.
(B) Conditions for the formation of electrovalent bond
(i) The atom which changes into the cation (+ ive ion) should have 1, 2 or 3 valency electrons. The other atom which changes into the anion (-ve ion) should have 5, 6 or 7 electrons in the valency shell.
(ii) A high difference of electro negativity (about 2) of the two atoms is necessary for the formation of an electrovalent bond. The Electrovalent bond is not possible between the similar atoms.
(iii) There must be overall decrease in energy which means that the energy must be released. For this purpose an atom should have low value of Ionisation potential and the other atom should have high value of electron affinity.
(iv) Higher the lattice energy, the greater will be the case of the forming an ionic compound. The quantity of energy released when free ions combine together to form one mole of a crystal is called lattice energy (U). Lattice energy is inter nuclear distance.
The energy changes in the formation of ionic compounds from their constituent elements can be studied with the help of a thermochemical cycle called Born Haber cycle.
Hope this helps mate ☺️.